DEPARTMENT OF TERRESTRIAL MAGNETISM J. A. Fleming, Director Scientific Results of Cruise VII of the Carnegie during 1928-1929 under the Command of Captain J. P. Ault BIOLOGY- 1 The Copepods of the Plankton Gathered During the Last Cruise of the Carnegie CHARLES B. WILSON CARNEGIE INSTITUTION OF WASHINGTON PUBLICATION 536 WASHINGTON, D. C. 1942 DEPARTMENT OF TERRESTRIAL MAGNETISM C3H- y |. A. Flemine, Director , ^— I "^ i Scientific Results of Cruise VII of the Carnegie during 1928-1929 under the Command of Captain J. P. Ault BIOLOGY-I The Copepods of the Plankton Gathered During the Last Cruise of the Carnegie CHARLES B. WILSON CARNEGIE INSTITUTION OF WASHINGTON PUBLICATION 536 WASHINGTON, D. C. 1942 IV PREFACE Captain W. J. Peters laid the broad foundation of the work during the early cruises of both vessels, and Captain J. P. Ault, who had had the good fortune to serve under him, continued and developed that which he had so well begun. The original plan of the work was envisioned by L. A. Bauer, the first Director of the Department of Ter- restrial Magnetism, Carnegie Institution of Washington; the development of suitable methods and apparatus was the result of the painstaking efforts of his co-workers at Washington. Truly, as was stated by Captain Ault in an address during the commemorative exercises held on board the Carnegie in San Francisco, August 26, 1929, "The story of individual endeavor and enterprise, of in- vention and accomplishment, cannot be told." Dr. Charles Branch Wilson, the last of that outstand- ing group of great monographers of the marine copepods which included Brady, Dana, Giesbrecht, Sars, and Thomas and Andrew Scott, died August iS, 1941. Thus the printing of this report on the copepods gathered on cruise VII of the Carnegie could not have his super- vision. We are indebted to Dr. Waldo L. Schmitt, Cura- tor of the Division of Marine Invertebrates of the United States National Museum, and his associates for certain necessary additions to the manuscript, for reading it, and for clearing up a few questions raised in the editorial revisions by the Office of Publications of the Institution and by Mr. C. C. Ennis of the Department of Terrestrial Magnetism. All Dr. Wilson's records and his very complete library of copepod literature were bec|ueathed to the Division of Marine Invertebrates, United States National Museum, Washington, D. C. It is hoped thai the recipients of this posthumous work of Dr. Wilsons will continue to con- tribute any publications of their own dealing with cope- pods or marine biology to the Wilson library at the National Museum, in order that it may be kept as up to date as possible. It is fitting to quote here Dr. Schmitt's appraisal of this memoir in an obituary notice, where, in referring to the three major manuscripts written by Dr. Wilson during the last decade, he says of this one: "It, perhaps the most important in Dr. Wilson's own opinion, deals with the copepods of the marine plankton taken on the last cruise of the ill-fated nonmagnetic yacht Carnegie. This report, which was submitted for publication several years ago, for the first time in the history of oceanography gives the directly comparable results of simultaneous three-level tows made in all oceans with identical gear, accompanied by full station data, including temperature, salinity, density, phosphates, and hydrogen-ion concentration. In his painstaking tabulation of the species of copepods in every haul and their abundance at each of the three levels investigated, involving the microscopic inspection of many thousands of individual copepods. Dr. Wilson has made available a biologic record of a group of organisms of highest importance in the economy of the seas such as has never been achieved by any marine expedition." J. A. Fleming Director. Department of Terrestrial Magnetism CONTENTS Introduction PAGE I Apparatus and Methods . . i Nets I Localities 2 Depth of Tow 2 Time of Tow 2 \'olume of Tow ( Pacilic Stations Only) 2 Qualifying Conditions 2 Nets 2 Depth of Tow 4 Supplementary Data 4 Oceanic Currents 4 Comparisons of Plankton Comparison of the Two Oceans Comparison of Different Regions of the Pacific Diversity of Distribution 8 Daytime Stratification 8 Causes of Daytime Stratihcation 9 Temperature . 9 Salinity (Map 3) and Density 11 Hydrogen-Ion Concentration 11 Phototropism 11 Lists of Species by Stations 15 Discussion of Species (Alphabetically Arranged) 169 Literature Cited 211 List of Species Discussed 215 Figures 1-136 218 Index 235 77504 THE COPEPODS OF THE PLANKTON GATHERED DURING THE LAST CRUISE OF THE CARNEGIE INTRODUCTION During cruise VII, 1928-1929, of the nonmagnetic vessel Carnegie extensive collections of plankton were made over parts of the Atlantic Ocean north of the equator and of the Pacific Ocean from 52° north latitude to 40° south latitude. The present paper deals only with the copepods of this plankton, their identification, and their actual and rela- tive distribution. In order to facilitate a correct interpre- tation of the records herewith presented, a preliminary account is given of the apparatus and methods employed. Certain qualifications also, which materially influence the conclusions to be drawn from the records, are dis- cussed somewhat at length. By this means, it is hoped that whatever might otherwise prove to be erroneous or illogical may be removed so that the ultimate conclusions may become rational, trustworthy, and instructive. The following four species and the first two genera are here described for the first time: CarnegiMa gracilis, new genus and new species, page 176 Danodes plumata, new genus and new species, page 182 Onchocalanus nudipes, new species, page 199 Scolecithricella spmacantha, new species, page 208 APPARATUS AND METHODS Nets The townets used on the Carnegie were the ordinary conical one-meter and half-meter nets of fine-meshed bolting silk. These were reinforced in the usual manner with canvas at either end and with both circular and longitudinal ribs of stout tape in the space between the canvas ends. The same nets were used throughout the entire cruise and always in the same manner, to insure a uniform basis of comparison between the different tow- ings. These nets could not be closed, but remained wide open while being lowered to and raised from the 50- meter and 100-meter levels. They were carefully cleaned after every towing so that there should be no mixing of species from different stations. [The following description of the nets used on the Carnegie is from H. R. Seiwell's article "Patterns for conical silk plankton nets of one-meter and half-meter diameters" as published in ]our. Conseil Internal. Explor. Mer, vol. 4, pp. 1)9-103 (1929). — Ed.] The nets are of sizes (a) one-meter diameter and 4'/^ meters long (the Michael Sars net), and (b) one-half meter diameter and 2 '4 meters long. Both were made from silk bolting-cloth of different meshes with canvas-collars at the top and bottom to hold the net-ring and collecting bottle, respectively. The nets (a) were made in three different meshes and the nets (b) in two different meshes since the filtering characteristics of a net must be according to the kind of plankton to be collected. Dufour silk bolting-cloth of sizes oooo(XX), o(XX), 2(XX), 5(XX), lo(XXX), and i5(XXX) was used exclu- sively for the filtering surface, and eight-ounce double-filled, white, extra duck for the canvas-collars. The seams were taped with inch-wide, fine woven linen or cotton tape, and the silk was sewed with the best quality No. machine twist- silk thread. Fine woven cotton tape i!4 inches wide was used for the three-meter horizontal seam which also served to hold the small brass rings to guide the throtde-line. One- inch pearl buttons of good quality were sewed with a strong linen thread to the double canvas-collar, all button holes being machine-made. The one-meter (outside diameter) brass rings for nets (a) were made of three-quarter-inch rod and the half-meter (out- side diameter) brass rings for nets (^) of half-inch rod. The silk pieces were joined together by a one-inch French seam, which was taped on the outside and held in place by two additional rows of stitching. . . . Three sizes of silk were used in making the Michael Sars net one meter in diameter at the mouth, tapering to a diam- eter of o.io meter, and 4.5 meters long, in the following combinations. Section Combination I 2 3 (i) Upper, 0.5 meter long , 0000 (XX) coon (XX) 0000 (XX) (2) Middle, I meter long . . lo(XXX) 5(>;X) o(XX) (3) Lower, 3 meters long . I5(XXX) lo(XXX) 2(XX) Two sizes of silk are used in the one-half meter net which is one-half meter in diameter at the mouth, tapering to a diameter of 6 cm, and has length of 2.75 meters. . . . These nets were used in the following combinations: (i) upper section of length 0.75 meter made of silk bolting-cloth of size 5(XX) and the lower section 2.0 meters long of size lo(XXX); (2) the upper section of length 0.75 meter made COPEPODS OF LAST CRUISE OF CARNEGIE of silk bolting-cloth of size lo(XXX), and the lower section 2.0 meters in length of size I5(XXX). Localities Tows were taken at each of the i(>2 stations designated on the accompanying map (map i), though tows at only 15S regular stations were considered.' Enough others were taken between the stations to bring the total of the localities up to 208. Not including 3 localities in the North Sea, only 39 of these localities are in the Atlantic Ocean, the remaining 166 being in the Pacific Ocean. As a result the Pacific is well covered from 52° north latitude to 40° south latitude, but in the Atlantic the stations are all north of the equator. This disparity was not inten- tional, but was due to the unfortunate destruction of the Carnegie at the close of the first half of her cruise. The second half of the cruise had been planned to include the southern part of the Pacific between 40° and 60° south latitude, the South Atlantic from the equator to 60° south latitude, and the entire Indian Ocean. This would have furnished data of supreme value for a comparison of the plankton of the three oceans. It is fortunate that, in accordance with the Carnegie's rule to forward imme- diately to Washington at each port of call all accumulated data and collections, no data or plankton collections were lost at Samoa in the destruction of the vessel. Depth of Tow At each of the regular stations three tows were taken, one at the surface, a second at 50 meters, and a third at 100 meters. The second and third nets were attached to the same wire; the surface net was on a separate wire, but was towed simultaneously with the other two. All the nets were drawn horizontally for a sufficient distance to obtain an excellent sample of the plankton at each of the three depths. The length of the tow varied consider- ably and is recorded for the Pacific stations only (pp. 42- 168). All the tows between the regular stati(jns, with one or two exceptions, were taken at the surface only when the vessel slowed down sufficiently or was becalmed. No vertical tows were made, with the single exception of one at station 64, and this was also the only one below 100 meters in depth. Time oh Tow All the tows at the regular stations were started at 8''3o'" A.M. local mean time, the time of completion varying with the length of the tow. Thus they were all daylight tows taken at about the middle of the forenoon, and none taken during the afternoon, evening, or night. This regu- larity of the time of the tows adds greatly to their value for purposes of comparison. The surface tows between stations, being dependent on the slowing down or becalming of the vessel, never came regularly but were taken at any time during the twenty-four hours, most often at night. They thus supply valuable data with reference to the migration upward of certain species of copepods during the night. Volume of Tow (Paciitc Stations Only) The volume of the tow was computed by allowing it to settle to the bottom of the bottle and measuring its depth. However deficient this method may be with refer- ence to the actual bulk of the plankton, it does supply a reliable basis of comparison when followed uniformly. When considered in connection with the length of the tow, it furnishes an accurate estimate of the comparative richness of the plankton in any locality. QUALIFYING CONDITIONS Nets It is stated above that the nets used in the 50- and 100- meter tows could not be closed while being lowered and raised. In other words, these two deeper tows were not exclusively horizontal, but included also a vertical or diagonal tow to the surface. This means that copepods could get into them at levels nearer the surface than the recorded depth of the tow. In all probability such intrusion of individuals from a ' For stations 129, 131, 161, and 162, apparently Dr. Wilson clitl not find any material for this report. — En. different level actually occurred more or less frequently. But the percentage of these aliens is small, as can be seen by the number of species in each station list recorded exclusively from the two upper levels. Any species con- fined to the 50- or 100-meter level would not be affected by other species coming in from higher levels. But if even one or two specimens of a species which was really con- fined to the surface got into the 50- or the lOO-meter net, it would indicate the presence of that species at a level where it did not really occur. The comparatively small percentage of species found at all three levels and the comparatively large percentage of species confined to a 4 single leve ire good proof ilial tlie mixing of different levels was rare. The relative abundance of any species at different levels will also prove helpful in deciding where it really belongs. For example, suppose a species is suffi- ciently abundant at the surface to constitute 80 or 90 per cent of the surface tow, as sometimes occurred, and only one or two specimens are found in the tows at lower levels. It is reasonable to infer that the latter specimens do not really belong to the deeper tow, but entered while the net was being raised or lowered. There will neces- sarily be some mixing of levels, but it is so slight as to be practically negligible, and none of the important results here considered is at all affected by it. Depth ok Tow Since the lowest depth at which tows were taken (with one exception) was 100 meters, whereas the depth of the bottom at all but 5 of the stations ranged from 2000 to 8000 meters, it follows that the entire towing was prac- tically at the surface. We are concerned here, therefore, with the epiplankton exclusively, and not at all with the bathyplankton. This means that the range of the species here recorded must be regarded as essentially a surface- area distribution, and only incidentally as a depth distri- bution. This consideration is of special importance in comparing the present records with those of other expe- ditions, notably the Challenger, Siboga, and bathypelagic Monaco expeditions. It is obvious that none of the numerous rare and often unique species obtained at depths ranging from several hundreds to even thousands of meters can be expected in these surface tows. Their absence from these records, therefore, is no indication that they were not present at the localities examined, but simply that the nets did not descend far enough to secure them. On the other hand, the presence in these tows of certain species obtained by other expeditions in vertical tows starting from considerable depths shows that such copepods cannot be regarded as exclusively bathypelagic. The Siboga expedition yielded the largest total of species thus far recorded. But at every station of that expedition whose record of species totaled above 70, the towing was done with a Hensen vertical net starting from depths of 700 to 2000 meters. These same deep ver- tical tows included most of the new species that were obtained. In view of these considerations, the facts that the Carnegie stations from 35 to 44 inclusive averaged 83 species, and that several other stations yielded species totals of from 90 to over 100, assume a greatly enhanced significance. These facts should be kept constantly in mind also when comparing the Carnegie records with those of the Challenger, Siboga, and Monaco expeditions. COPEPODS OF LAST CRUISE OF CARNEGIE SUPI'LEMEN'TARY DaTA In the station lists of species herewith presented there arc included statistics regarding certain factors which have considerable significance in copepod distribution. The Carnegie Institution of Washington has furnished the author with blueprint lists showing the temperature, salinity, density, and hydrogen-ion concentration of the sea water at the three tow depths for each station. These data are reproduced here, but those pertaining to condi- tions of the weather, sky, and sea at the various oceano- graphic stations are not given in this report inasmuch as they are to be published in other volumes of this series giving the observed data and discussions relating to physical oceanography and to meteorology. A second blueprint list supplies for the Pacific stations (35 to 162) the total volume of the plankton for each of the tows and the distance through which the net was drawn to secure that volume. The data for volume and distance are not available for the 34 Atlantic stations except in one or two instances. The lists of copepod species from the three tows at each station have been kept separate, and there is also recorded the comparative abundance of each species at the three depths. All these data are incorporated in each station list be- cause it is believed that they are fully as valuable as the lists of species themselves. As far as is known, such data have never before been presented in connection with station lists. They furnish practically all the information that can be obtained with reference to each locality. Without them the list is devoid of any information ex- cept the mere names, and becomes practically meaning- less. Oceanic Currents The surface currents of both the Atlantic and Pacific oceans were fairly well known and had been charted before this cruise of the Carnegie. The observations taken during the present cruise confirm previous discoveries and add a great many of the missing details. Very much less is known about the deep-sea currents, but since all the Carnegie tows were confined to the upper 100 meters of water, these deeper currents would not affect them so much as would those at the surface. The thing that con- cerns us most in dealing with the copepods is the evi- dence of an intimate relation between the surface cur- rents and plankton distribution. The only surface current of any importance in the North Atlantic is the well known Gulf Stream. This was crossed several times by the Carnegie, and its influence was chiefly manifested in an increase of the copepod plankton, both in species and in numbers. There were COMPARISONS OF PLANKTON also some of the usiuil instances of a northward trans- portation of species whose normal habitat was farther to the south. The course of the Carnegie in the Athmtic did not come in contact with other surface currents, and con- sequently the station lists of copepods cannot give us more than this minimum of evidence with reference to the influence of the currents on the plankton. A similar relation between the Gulf Stream and the volume of the plankton was shown by Jespersen (1926) in his discus- sion of the quantity of macroplankton in the North Atlantic, but species were not mentioned. In the Pacific Ocean, however, conditions are very dilTerent. In one of the papers already published by the Carnegie Institution of Washington, Sverdrup has made use of the map of the surface currents of the Pacific which is here reproduced (map 2). This map shows an approximately symmetrical surface circulation north and south of the thermal equator, which is a few degrees north of the geographic equator. In the South Pacific the west-wind drift generates a current flowing east and striking the western coast of South America, where it is deflected to the north along the coast as the Peruvian Current. At the equator this current is turned back west- ward across the central Pacific as the South Equatorial Current. A part of it flows directly west to the East Indies, another part flows southwest to Australia. In the North Pacific the west-wind drift forms the Japan Current, which flows eastward and, striking the western coast of North America, is deflected to the south as the California Current. This follows the coast to the southern boundary of Mexico, where it is turned west- ward as the North Et]uatorial Current; this flows directly west to the Philippine Islands, where it joins the Japan Current. Between the two equatorial currents, both of which flow west, is a countercurrent flowing east along the thermal equator and striking the western coast of Central America. Here it divides, one half turning sf)Uth and then west and joining the South Equatorial Current, the other half turning north and west and joining the North Equatorial Current. The course of the Carnegie followed part of each of these currents. Stations 35 to 40 were in the half of the eastern end of the Counter Equatorial Current that turns south and west. Stations 40 to (So were within or close to the Peruvian Current. Stations 93 to 98 were in the South Equatorial Current. Stations 102 to no were in the North Equatorial Current. Stations in to 115 were in the Japan Current. Stations 12S to 135 were in the Cali- fornia Current. Stations 150 to 160 crossed the North and South Equatorial and the Counter Equatorial currents. The above stations in every instance were the ones that yielded the greatest variety of copepod species and the largest number of individuals. There must be something, therefore, in connection with these currents which is con- ducive to copepod life and development. Sverdrup has plainly shown a combination of low salinity and low temperature near the surface in the Peruvian Current, and this combination appears to a greater or lesser degree in each of the other localities mentioned above. We cannot escape the conclusion that such a combination is favorable to the copepods, or at least not antagonistic. There is also the probability of better aeration of the water in these currents than outside of them, and the possibility that they contain a richer and more uniform supply of food than can be found in water that does not flow. COMPARISONS OF PLANKTON Since all the regular tows were made at the same time of day, by the same persons, using the same nets, and employing the same methods, the species lists will be as free from diversity as they could possibly be. If we com- bine with these lists of species the supplementary data mentioned above, we find ourselves in possession of an accurate and really scientific basis for a comparison of the copepod plankton of the two oceans and of the dif- ferent parts- of each of them. Comparison' of the Two Oceans The Carnegie towings show that the Pacific plankton is much richer in copepod species than that of the Atlantic over those parts of the two oceans covered by the cruise. For instance, station ^4, the last one in the Atlantic, may be compared with station 35, the first one in the Pacific. These two stations are about equally distant from the two ends of the Panama Canal; the bottom depths are each over 3500 meters, with a difference of only 47 meters. The Atlantic station yielded 48 species; the Pacific station yielded 96 species. On comparing sta- tions 15 to 25, down through the center of the North Atlantic, with stations 1^0 to i :;5 and 14S to 152 at cor- responding latitudes in the Pacific, we get a total of 394 species for the Atlantic stations with an average of 56 per station, and 661 species for the Pacific stations with an average of 66 per station. Unfortunately the total volume of the plankton is not recorded for the Atlantic stations, but in view of the great inferiority in number of species it is reasonable to assume that it was much less than that at the Pacific stations. COMPARISONS OF PLANKTON Tlie largest number of species at a single station in the Atlantic was 60, at station 23, and half the stations had each a total of less than 25 species. Pacific station 56 yielded 108 species; 14 stations yielded iSo to 96 species each, and 17 stations from 71 to 78 species each. At only 15 (12 per cent) of the 124 Pacific stations did the species total fall below 25. The entire number of different species obtained from all the Pacific stations was 265, whereas the Atlantic stations yielded only 132. Thus in the Car- negie towings the Pacific yielded, on the whole, 100 per cent more copepod species than the Atlantic. But there are some excellent reasons why this ratio, although it is entirely correct for the Carnegie material, should not be too hastily adopted as true for the entire plankton of the two oceans. In the first place, only a part of the North Atlantic was covered by the Carnegie tow- ings. If the North and South Atlantic had been as com- pletely towed as were the North and South Pacific, the result would certainly have been different. In other words, the comparison is only a partial one. In the second place, the cruise of the Carnegie covered those parts of the Pacific which have been found by other investigators to be most prolific in copepod species. On the contrary, the parts of the North Atlantic that were included are regarded as the least prolific by all who have investigated the Atlantic plankton. The comparison, therefore, not only is incomplete, but also favors the Pacific to a con- siderable degree. Jespersen (1926), in discussing the tjuantity of macroplankton obtained in the Atlantic by Danish investigators, concluded that the minimum volume in the upper 100 meters was to be found in the western Atlantic between 20° and 30° north latitude, in the Caribbean Sea, and in the Sargasso Sea. The last two are the parts traversed by the Carnegie, which did not touch the regions of maximum volume. Jespersen stated that around the Azores the volume of plankton was 20 to :;o times as large as in the Sargasso Sea. If the region of the Azores, therefore, and other more prolific regions of the Atlantic had been included in the cruise of the Carnegie, the comparison of the plankton of the two oceans would have been much less favorable to the Pacific. In the third place, as has already been shown, more than half the Pacific stations came within the in- fluence of surface currents, whereas only a few of those in the Atlantic were so situated. If these currents are really as conducive to copepod plankton as they appear to be, this is another advantage for the Pacific. All these reasons are well worthy of consideration, but in spite of them it does not seem as if the inclusion of the more prolific parts of the Atlantic would produce enough additional species to take away the supremacy established by the Carnegie material for the Pacific. In looking for an explanation of the small number of species found in the Sargasso Sea and in the Caribbean Sea, we may note that at the stations which are compared above we find in the Atlantic a comparatively high temperature combined with an exceptionally high salinity. A high salinity is known to be adverse to ordinary pelagic copepods, and it is possible that when combined with a fairly high temperature it may become a deterrent to copepod life in the epiplankton. It is worthy of comment that there was not found in the Pacific any trace of such countless swarms of a single copepod species as are often seen of Calaniis finmarchiciis at certain seasons in the North Atlantic. They may exist in the Bering Sea north of the Aleutian Islands, but this region was not visited by the Carnegie. Comparison ov Different Regions of the Pacific Although the Carnegie towings thus are inadet^uate for a satisfactory comparison of the plankton of the two oceans, they do furnish an ideal basis for comparing the copepod faunas of the different regions of each ocean, especially of the Pacific. They are extensive enough to include adequate samples from practically all the im- portant regions of the ocean, and at the same time they furnish enough data with reference to the environment in each of the regions to explain the differences that appear. As has been found by all other investigators, the trop- ical parts of the ocean are richer in species than the tem- perate regions, but the tow is often inferior in volume. The plankton of the South Pacific contained a greater number of species than were found in the North Pacific, but the volume of the tow reached its maximum in the northernmost part of the ocean. In the South Pacific the stations yielding the most species were located in the eastern part alongside the Humboldt Current and in the western part north of the Samoan Islands. In the North Pacific the richest stations were found off the coast of Japan in the western part, and halfway between San Francisco and the Hawaiian Islands in the eastern part. Station 56, situated in latitude 31° 49' south and longi- tude 109° 04' west, yielded 108 species and becomes thereby the banner station of the entire cruise. Station 55, outside the Pacific end of the Panama Canal, was second with 96 species, and station 113, close to the eastern coast of Japan, was third with 93 species. Stations 40 and 109 were fourth, each with 90 species. The last of these, num- ber 109, was the station above the newly discovered Fleming Deep, the depth of the bottoiTi being 5252 meters. There were 9 stations each yielding from 80 to 88 species, 18 stations each with 71 to 78 species, 16 stations each with 60 to 69 species, and 26 stations each with 50 to 59 species. This makes a total of 75 stations, or 59 per cent 8 COPEPODS OF LAST CRUISE OF CARNEGIE of those in the Pacific, each listing 50 species or more. In the Atlantic, the Caribbean Sea stations yielded a larger number of species than those in the Sargasso Sea. But, as already stated, both these regions were found by Jespersen (1926) to be much inferior to other parts of the North Atlantic. Diversity of Distribution We have just seen that there is great disparity in the quantity of macroplankton obtained from different localities of the various oceans. In dealing with the copepods we may go farther and say that there is not a single species that does not show more or less diversity in its distribution. In more than 90 per cent of the species the diversity is so great that it becomes the predominant feature of the distribution. This diversity is evident not only in the horizontal or geographic distribution, but even more in the vertical distribution, as will be shown later. Any attempt, therefore, to calculate the number of copepods per liter or per cubic meter of the ocean water gives us no practical information. One might as well try to calculate the number of gulls and terns per cubic meter of the atmosphere above the ocean. The recurrence of specific names in successive station lists might suggest at first thought a more or less uniform distribution. But when we consider the relative abun- dance, we are likely to find that the species was repre- sented at one station by hundreds of individuals, whereas perhaps at the very next station the entire tow had to be carefully examined in order to secure a single specimen. The concept of diversity is greatly strengthened by a study of the data contained in the station lists here recorded, especially those on relative abundance. Simply the name of the species has heretofore been recorded, and usually we have been left in complete ignorance of its comparative abundance and its vertical distribution. The interesting and valuable information which may be derived from such data furnishes an abundant warrant for their publication. Of the 263 different species recorded from 166 localities in the Pacific Ocean, 105 appear at 5 localities or less, 60 being each confined to a single local- ity. Of the remainder, 120 species are restricted to a total of 50 localities or less, which is only a two-sevenths dis- tribution. Only 7 species, or less than 3 per cent of the entire number, have any claim to universal distribution, and each of them shows great diversity in its relative abundance. A remarkable instance of inequality in distribution is shown by two surface tows taken between stations 50 and 51. The tows were made consecutively at the same locality, on the same day, and with the same net. To- gether they yielded 42 species, and 23 of these, or more than half, were found in one tow only and did not appear at all in the other. Two surface tows between stations 62 and 63, taken on the same day, with the same net, but a short distance apart, yielded 50 species, 32 of which, or 64 per cent, were confined to one of the tows. Between stations 65 and 64 three surface tows were made on January 2 and three others on January 5, all with the same net, but short distances apart. The first three tows yielded 44 species, of which 26 appeared in one tow only. The second three tows gave a total of 37 species, and 22 of the.se were found in one tow only. Such data not only confirm the irregularity of distribu- tion in the plankton, but also suggest that, even in restricted areas, what may be termed the "personnel" of the plankton is constantly changing. Two tows over the same area, no matter how quickly one may follow the other, will never yield identical results. Having thus established the lack of uniformity in the horizontal or geographical distribution of the copepods, we turn to their vertical distribution. Daytime Stratification The different species of copepods that are found near the surface of the ocean in the daytime show a marked tendency to arrange themselves in zones or layers parallel \vith the surface. Some species are practically confined to the surface tows, of which they often constitute a very large percentage, rarely as high as 90 to 95 per cent. Others are confined entirely or very largely to the 50- meter tow, and still others apparently do not approach nearer to the surface than the lOO-meter tow. If the station lists are compared, it will be found that this stratification is apparent in every one of them. Per- centages large enough to constitute definite evidence of layering are always present. This does not necessarily mean that any one species is always and everywhere found at one of the three depths and never at either of the other two, although even that is true in some instances. But it does signify that at the time the tow was taken and under the existing conditions, very re- spectable percentages of the copepods showed a decided preference for one of the three depths to the exclusion of the other two. On an average, about half the copepods present at each station show such an exclusive preference, and most of the other half show a similar but less marked liking for some one of the zones. They are found in abundance in the preferred zone, but only rarely or in small numbers in the other two zones, being often wholly absent from one of them. In all probability a closing net would eliminate many of these secondary appearances and credit more species with exclusive preference for the zones where they were most abundant. Two or three COMPARISONS OF PLANKTON examples will illustrate the evidences of such stratifica- tion more clearly. The list for station :;5 shows lo species confined to the surface tow, i^ to the 50-meter tow, and 24 to the 100- meter tow. Forty-seven species, therefore, out of a total of 96 showed definite selection of a single depth to the exclusion of the other two. Thirty other species were found in two of the tows but not in the third one, thus manifesting a similar but less exclusive selection. Fur- thermore, in only 2 instances do we find the abundance records of any species in the two tows exactly the same. In 7 other instances, however, both records are expressed in numerals, with not enough difference between them to warrant any assumption of real preference. Eliminating these 9 records, the other 16 species do manifest a more or less decided preference for one of the two depths over the other. Finally, there were 19 species which were found at all three depths. In 5 instances the abundance record was exactly the same at the three depths. For 9 other species it was the same at two depths and differed in the third. In the remaining 5 species the records show a de- cided preference for one depth over the other two. Of the 96 species taken at this station, therefore, 61S (71 per cent) showed good evidence of selection in the depth at which they were found. In the list for station 56, 49 species were restricted to a single depth, 44 were taken at two depths but not at the third, and 15 were present at all three depths. Of the 44 two-depth species, 19 showed a definite preference for one depth over the other, and of the 15 three-depth species, 11 distinctly favored one of the depths in prefer- ence to the other two. Here, then, 79 species (7^ per cent) manifested a choice of depth. At station 51, 39 of 50 species were confined to a single depth; 10 others were present at two depths, with 6 of them preferring one of the depths to the other. A single species was found at all three depths, with the same record for two of them and a much smaller one for the third. Here, then, 45 species (90 per cent) showed selec- tive stratification. Every one of the lists gives evidence of similar stratifi- cation of the copepods captured at the station. The num- ber of species manifesting an exclusive preference for one depth only and those that were present at all three depths arc recorded in the remarks accompanying each station list. The former constitute from 50 to 90 per cent of the species total in three-fourths of the station lists, and in the other fourth they fall below 40 per cent only twice. The species present at all depths vary from o to 30 per cent of the species total, with an average of about 15 per cent. Among these species the number of instances in which the abundance record is the same for all three depths is so small as to be practically negligible. Sum- ming up the evidence here presented, we find that almost every species in each of the station lists shows some degree of preference as to depth. Causes of Daytime Stratification We naturally look for the cause of this universal day- time stratification within the upper 100 meters of the ocean. Is it the salinity, the temperature, the density, the hydrogen-ion concentration, any combination of two or more of these factors, or the united effect of all of them? Or may it be something outside, more powerful than any of them, or even than all of them combined? Since we have the necessary data in connection with the station lists, some answer to these questions ought to be possible. Let us consider the data separately, beginning with tem- perature. Temperature There is no doubt that temperature does exert con- siderable influence on copepod distribution. Is it strong enough to produce such a universal stratification? And if so, is there sufficient difference in temperature between the three depths at which the tows were taken to warrant its selection as the principal cause? At first it would seem as if the answer might be in the affirmative. The greatest variations in temperature of the ocean water are nearest the surface. The upper 100 meters, within which all but one of the Carnegie tows were taken, show the maximum differences between the various regions of an ocean — polar, temperate, and trop- ical. Here also are found the maximum differences in temperature between the vertical depths o, 50, and 100 meters. Below 100 meters there is a gradual approach to uniformity of temperature over the entire area of all the oceans. Variations in temperature are undoubtedly one of the causes of the marked differences in the copepod species that make up the regional plankton of the upper 100 meters. The Carnegie stations in the Pacific ranged from 52° north latitude through the tropics to 40° south lati- tude. The low temperatures of the upper 100 meters north of parallel 40° north entirely exclude many of the copepods that are common in the tropics. The number of species taken at each of the 12 stations in that part of the Pacific was thus reduced to an average of only 16. A comparison of this average of 16 with the average of 83 for stations 35 to 44 in the tropics suggests the powerful influence of temperature on regional distribution. Is its influence on vertical distribution equally great? These few species at the northern stations showed the same evidence of stratification as the more numerous species in the tropics. That this stratification is not due to the ver- 10 COPEPODS OF LAST CRUISE OF CARNEGIE tical differences in temperature, however, is apparent on examination of the station Hsts. At station 121, for ex- ample, the three tows yielded 18 species of copepods. Two species only were found at the surface, one of which was represented by development stages only, with no adults. Eleven species were present in the 50-meter tow, and 16 in the 100-meter tow. Two of the former and 6 of the latter were not present in either of the other two tows. The temperature at the surface was only 7^4 C; at 50 meters it dropped 4°, and at 100 meters i?5 more. If the variation in temperature were the reason for the copepods' choice of depth, the 16 species should have been found at the surface and not at the lOO-meter level. More- over, a difference of only i?5 would hardly be sufficient to cause a third of the entire number of species to locate at the lOO-meter level to the exclusion of the 50-meter level. At station 127, 14 species were obtained; 6 species were present in the surface tow, 6 in the 50-meter tow, and 10 in the 100-meter tow. Three species were confined to the surface, i to the 50-meter level, and 5 to the loo-meter level. The temperature at the surface was i3?3 C; it dropped 3° at 50 meters and 2° more at 100 meters. The same considerations as before preclude the assumption that the variation in temperature was the cause of the differences in depth of the copepod species. Any copepod that has become inured to living and breeding in water as cold as is found in these northern latitudes will not be much affected by changes of 2° or 3° in temperature. In the tropics, on the other hand, the water at the sur- face is much warmer and the differences in temperature between the three tow depths are sometimes large enough to appear like important factors in copepod zoning. At station 35, for instance, the temperature at the 100-meter level was 13° lower than at the surface. At station 39, on the equator, it was nearly 11° lower; at stations 71 and 72, latitude 10° south, it was about 10° lower. At station 109, over the Fleming Deep, there was a drop of 8°, at several of the stations north of the Hawaiian Islands the drop was 7° to 9°, and at a few stations southeast of the Hawaiian Islands there was a difference of 8° to 16°. These variations are all of sufficient magnitude to suggest an appreciable influence of temperature on stratification. An examination of the species lists at these stations re- veals exceptionally well marked stratification, but in every instance it is the exact opposite of what it should be, on the hypothesis that higher temperature induces greater concentration of copepods. The species were bunched at the two lower levels instead of at the two upper ones, and the loo-meter tow contained sometimes two or even three times as many species as were found at the surface. At station 152, the water at 50 meters was 13° colder than at the surface, and at the lOO-meter level it fell 3° more, a total drop of 60 per cent. Yet the 100- meter tow contained almost three times as many species as the surface tow, and the 50-meter tow nearly twice as many. Frequently, however, the tropical stations showed but little temperature change at the three tow depths. At station 46, for example, the difference in temperature between the surface and the loo-meter depth was less than 1°. Yet 4 species were restricted to the surface tow, 5 to the 50-meter tow, and 13 to the loo-meter tow. At stations 91 and 9:; the difference in temperature between the two tow depths (0 and 50 meters) was o?2, but 80 per cent of the copepod species were present in one tow and absent from the other. At station 80 the difference in temperature between the two depths was only o?i, but 1 1 species were confined to the surface tow and 23 to the 50-meter tow. A difference of o?i in temperature would hardly constitute a sufficient incentive for the exclusive stratification of 63 per cent of the 54 species captured at this station. At station 81 exclusive stratifica- tion was shown by 70 per cent of the 47 species, with only 0?! difference in the temperature of the two tows. At station 82 there was absolutely no difference in tempera- ture at the two tow depths, and still 70 per cent of the 52 species showed a definite choice of one of the depths to the exclusion of the other. At station 160 the temperature was exactly the same at all three depths, but 50 per cent of the species were confined to a single level, and 25 per cent more were present in two of the tows but absent from the third. Three-fourths of the species thus showed definite zoning without any temperature incentive. We are forced to conclude, therefore, that in most cases the temperature variation is not large enough to produce the amount of stratification shown; and when it does appear to be of sufficient size, it seems to have the opposite effect from what would be expected. In this connection it must be noted that some copepod species are not influenced by even considerable changes in temperature, and that many of them appear immune to low temperatures. Expeditions into both the Arctic and Antarctic regions have revealed species of copepods, accustomed to warmer regions, living in the icy waters of those regions, and apparently breeding freely. The same is true of the copepods that live at considerable depths in the temperate and tropical regions. A tow was taken July 20, 1953 in a closed net south of Georges Bank about 39 north latitude at a depth of 2000 meters. The net worked perfectly, going down closed, opening at the desired depth, and closing again before being drawn up. An examination of this tow revealed hundreds of Metridia belonging to four different species, and also specimens of Rhincalaniis, Eiicalanns. Pareuchaeta, Centropages, Het- erorhabdiis, Luciciitia, HaloptiUis, Gaiditts, Pseitdochi- COMPARISONS OF PLANKTON n rella, Pleuromamma, and other genera. The temperature at 2000 meters was below 3° C, and yet these copepods seemed as healthy and active as other specimens of the same species captured within the upper 100 meters, where the temperature ranged from 15° to 21° C. It is evident that even considerable variations in temperature would affect such copepods very little, if at all. Salinity (Map ]) and Density In contrast with the temperature, both the salinity and the density differ so little within the upper 100 meters that they probably exert no influence on the vertical dis- tribution of the copepods. But they do appear to affect the regional distribution to a certain extent. The surface salinity is a little higher in the Atlantic than in the Pacific Ocean, which may be a contributing factor in the superior quantity and variety of the Pacific plankton. None of the Carnegie stations came within the area of maximum sur- face salinity in the North Atlantic, but those numbered from 22 to 34 were in the zone of minimum salinity, and it is worthy of note that they yielded a larger average number of species than any of the others. Again, the area of maximum salinity in the Pacific Ocean lies around the Society Islands. The Carnegie passed through this area, and the station lists from within it are below the average. All the stations where the largest numbers of species were obtained show salinities at or a little below the average. This would seem to indicate that such average salinities are most acceptable to copepods and that there is a tendency to avoid both extremes. The salinities and densities at the three tow depths are exactly the same in many of the station lists. When they do differ, it is within such narrow limits as to preclude any appreciable in- fluence on vertical distribution. Hydrogen-Ion Concentration The same statement may be made about the hydrogen- ion content of the sea water as about the salinity and density. The hydrogen-ion concentration is too often exactly the same for all three tow depths, and when it does vary the extent of the variation is too slight to war- rant an assumption that it has any material influence on the vertical stratification of the copepods. Pliototropism The preceding discussion has shown that neither tem- perature nor salinity, hydrogen-ion concentration, or density could produce the daytime stratification of which we find definite evidence in every station list of species. Temperature and salinity are concerned in the regional distribution of the species and may answer the cjuestion as to why a given copepod is found at one station or in one locality and not in another; neither density nor hydrogen-ion concentration appears to enter appreciably into even this kind of distribution. We are forced to look elsewhere for the cause of the daytime stratification. We must search for something that is everywhere present in the daytime, that is at work all the time from dawn to dusk, and that is strong enough to produce definite and uniform results even in the face of antagonistic influences. The very fact that this is a daytime stratification suggests sunlight as its cause, and after the elimination of every- thing else, this is the only cause left that answers all the requirements that have just been enumerated. It has been found by many observers that light is the most important factor controlling the nocturnal migra- tion of copepods, and it is perfectly Icjgical that it should also control their diurnal movements. Many species of copepods in both salt and fresh water migrate regularly from greater or lesser depths toward the surface as soon as it begins to be dark, and begin to return between mid- night and sunrise. It is evident that the depth from which a copepod will be able to reach the surface is necessarily limited by its swimming ability. The jerky movements characteristic of copepod locomotion are not conducive to even moderate rapidity, and they are never continued steadily for any length of time. The progress is always leisurely, interspersed with frequent rests and periods of floating. The only occasion when a copepod tries to move rapidly is in an attempt to escape impending danger, and even then its efforts are spasmodic and nearly always futile. Moreover, its course is never in a straight line for any considerable distance, but is full of turns and twists and often spiral movements. Another fact must also be considered, namely, that the interval between sunset and sunrise varies greatly with the season of the year and with the latitude of the loca- tion. All the Carnegie stations were located in the tropical and temperate zones. The observations in the North Atlantic were made from the middle of May to the first of October, those in the South Pacific from the first of November to the last of April (southern summer), and those in the North Pacific from the first of May to the middle of October. .At practically every one of the stations, therefore, the time of year and the latitude were such as to give considerably reduced periods of darkness, with a corresponding increase in the periods of daylight. Such considerations lead inevitably to the conclusion that the diurnal migrations are confined to the upper layers of the ocean water and do not reach any con- siderable depth. It would, seem as if from 100 to 150 meters were about the lowest depth from which the average copepod would be able to reach the surface. But of course the migration is not limited by the copepod's ability actually to reach the surface within a given period. It undoubtedly takes place down to the limit of 12 COMPARISONS OF PLANKTON 13 light pcnctr.ilion. Altliou^li the copcpcicls taking part in this deeper movement would not reach the surface, they might he foLUid at tiie 50-meter or 100-meter level during the night. If it be true that the coming of daylight furnishes the incentive for the departure of the copepods from the surface, it follows that the depth to which they retire below the surface will vary with the intensity of the light. : They will descend farther on a bright, sunny morning than when it is cloudy and lowering. On a day that is ushered in with clouds so dark and gloomy that the sun- shine can scarcely penetrate them at all, the copepods may well stay near the surface long after sunrise and descend but a short distance. The varying intensity of the light offers a good explanation of the fact that some species are found close to the surface at one station and considerably removed from it at another, perhaps the very next one. Damas and Koefoed (1907) summed up their work on the plankton of the Greenland Sea as follows: "At any given place the organisms are distrib- uted according to the degree of light for which they are sensitive. They rise and fall according to the daily varia- tions in light intensity. The level at which a form remains is different from sea to sea. Species which live at the sur- face in the polar sea are found in the depths under the equator. Others that are seen to exist in the intermediate layers in the north are only found in the abyss at the south." Russell (1927/') confirmed these statements antl added that copepods also show seasonal variation in their vertical distribution, going deepest in mid-June when the light intensity is greatest. Again, we cannot expect the same intensity of light to affect different species equally, and here we have a reason for the fact which is so evident in every one of the station lists. Some species remain at the surface no matter how intense the light becomes; the others migrate downward but stop at different levels according to the amount of influence exerted on them by the light. We are thus en- abled to understand how it is that the copepods become so distinctly stratified at every one of the stations in the daytime and also why we find the same species concen- trated in different strata on different days. Russell went farther and declared: "In the sea each plankton animal may have its own vertical zone in which it finds certain conditions most favorable. This zone varies for different species, for individuals of the same species at different ages and stages of development, and even for the different sexes." Although, therefore, this is not the first time that strati- fication of the plankton under the influence of sunlight has been proposed, it is here proved to exist among the copepods over a much more extensive area of two oceans than had hitherto been studied. The fact that every one of the station lists without exception gives definite evi- dence of this stratification would .seem to warrant the general statement that it exists everywhere in the open ocean during the daytime. Michael (1913) discovered a similar stratification among the chaetognaths of the San Diego region, California. He concluded that each species had its own definite and specific manner of vertical distribution just as truly as it had its own specific morphological characteristics, and that the two were more or less interrelated. Rose (1925) made an extensive study of the biology of the plankton at Roscoff on the coast of France. He included the entire plankton in his study and, among the other forms, six of the copepods most abundant at that locality. Later he repeated his Roscoff experiments with other copepods at Banyuls-sur-Mer on the Mediterranean. From these ex- periments he concluded that below a certain inferior light-intensity limit the copepods were positively photo- tropic, above a certain superior light-intensity limit they were negatively phototropic, and between the two limits they were indifferent. He concluded that the daily vertical migration is due to the following influences: (i) Sunlight provokes the movement, directs it, and partly regulates it. (2) Temperature modifies more or less the action of the light energy, and when high enough may even reverse the action of phototropism. These inter- actions between temperature and phototropism have been verified by other observers: Parker (K/J2) found that the females of Liibidoceni aestiiHi hatl a strong positive photo- tropism for light of low intensity, whereas the males had a weak negative phototropism; these were unaltered in both sexes by temperature changes between 10° and 35 C; in a strong light the female became negative, but the male was not affected. Russell (1928) found that Calanus fuimarchiciis was negative to light at medium tempera- tures but became positive at 13° C and strongly so below 10° C; Metridia liicens was negative at ordinary tem- peratures but became positive at 10° C; Acartia claiisti was strongly positive at ordiitary temperatures but the phototropism entirely disappeared at 28° C; Centropages hamatus was positive up to 25° C, then became more and more indifferent to light and was finally negative. (3) Salinity, chemical composition, dissolved gases, etc. are accessory factors but usually have little if any influence. In exceptional conditions they may become of great im- portance. These experiments were made near the shore in comparatively shallow water, where physicochemical conditions would have a somewhat increased influence. In the open ocean the influence of the temperature and accessory factors would be considerably reduced and that of the sunlight correspondingly increased. Rose (1925) suggested that the majority of the animals in the plank- ton are adapted to an optimum intensity of light, and 14 COPEPODS OF LAST CRUISE OF CARNEGIE that this varies with each species and possibly with each individual, and is affected by the physicochemical factors of its environment. The optimum zone of distribution changes with the age of the animal and with its physico- chemical state at any moment. This explains the fact that nearly all the copepods show a strong positive photo- tropism during their development stages, although many of them become negatively phototropic on reaching maturity. Russell (igiyb) confirmed this and added: "The gradual changes in vertical distribution throughout the life of an individual have been termed ontogenetic migrations." Russell (1925, 1926^, 1926^, i926r, 1927(7, 1928) has pub- lished several papers on "The vertical distribution of marine macroplankton." He deals with the entire plank- ton, especially the young of fishes, and devotes one paper to light intensity as a controlling factor in plankton dis- tribution (1926c, p. 415). He gives the vertical distribution of Calanits, Centropages, and Temora in water over 50 meters deep, at different hours of the day, under different intensities of light, and during different months of the year. We gather from these that the vertical distribution sometimes begins below the surface, attains its maximum at depths of 5 to 20 meters, and then diminishes and dis- appears before reaching a depth of 50 meters. This distri- bution was in water which was shallow as compared with the open ocean, but there is no reason why it should not occur also in the open ocean at least to some extent. If it does, then we should find communities in the 25- meter zone differing more or less from those at the sur- face and at the 50-meter level. In all probability, there- fore, a tow taken at the 25-meter level would contain species not found at the surface or at the 50-meter level. Similarly, the 75-meter level would probably be found to contain species different from those of the 5u-meter and loo-meter levels. We are thus forced to the inference that the Carnegie towings probably did not obtain all the species that occur within the upper 100 meters of the ocean water. Incidentally, also, these considerations indicate the in- adequacy of results obtained by daytime towings at the surface alone in an effort to determine the plankton of any given locality. The number of species thus obtained would constitute so small a fraction of the entire plank- ton at the locality that it would have but little value. A surface towing in the night, on the contrary, might give a very respectable indication of the total plankton, since many of the species that remain at deeper levels during the daytime come to the surface at night. To obtain satis- factory results, therefore, there must be tows at different levels during the daytime and these must be supple- mented by tows at or near the surface at night. LISTS OF SPECIES BY STATIONS As already stated, the station lists which follow contain all the available data for each station in reference to tem- perature, salinity, density, and hydrogen-ion concentra- tion. In addition, every species is recorded from the depth or depths at which it was obtained, and its relative abundance is given. For 5 specimens or less, the actual number is given. Above that number, the letter r (rare) indicates 6 to lo individuals; / (few), ii to 24; c (common), 25 to 50; and a (abundant), over 50. Actual count was made up to 25; above that, the numbers were estimated. This method of record gives us not merely the regional dis- tribution, but also the vertical distribution at each station, and reveals very clearly the stratification or layering of the copepod species during the daytime. Attention is again called to the fact that the three tows at all the regular stations were made at about the same time of day, which adds greatly to their value for purposes of comparison. In the remarks under each of the station lists are noted the important data for that station. The total number of species found at each depth is also given, together with the number and percentage of species which were con- fined to a single depth as well as the number found at all three depths. Comparisons are also made between the tows taken at the regular stations in the daytime and the surface tows made between stations, usually during the night. In many instances these comparisons reveal noc- turnal migrations to the surface on the part of some of the species. Station 1 May 12, 1928; 38° 14' N, 67° 34' W; bottom depth, 4900 m; 49 species Depth of tow, m Temperature, °C SaUnity, 0/00 24,0 36.2 70 22.5 36.4 c c { f f r f r c c f 1 f r f f c f f r f r r a c f c c c 2 f c c c r f f f r f c Depth of tow, m 70 Density ('nocera clausi Megacalanus longicornis. Microsetella norvegica. . . rosea Miracia efferata Oithona plumifera similis spinirostris Oncaea minuta venusta Paracalanus parvus Phaenna spinifera Pontella pennata Pontellina plumata Pseudocalanus minutus. . Rhincalanus cornutus. . . . nasutus Sapphirina angusta auronitens nigromaculata Scolecithrix danae Temora longicornis styHfera Undinula vulgaris c r r 2 3 c 1 3 r r c 1 3 19 2 c c a c 1 This station was just at the eastern edge of the Gulf Stream and showed a fairl)- high surface temperature, which fell only 1?5 in the upper 70 meters. The salinity, density, and hjdro- gen-ion concentration were practically the same at both depths, the differences being too small to affect distribution. Twenty-two of the species (46 per cent) were confined to a single depth, and 15 of the species found in both tows showed an appreciable difference in relati\e abundance. The two genera Corycaeus and Farranula yielded the greatest number of species and constituted a large bulk of the tows in spite of their diminutive size. This is the only Atlantic record for Corycaeus ovalis and Euchirella curticauda and is one of two Atlantic records for Euchirella pulchra; and Pontella pennata, a single female, is the only record of this species for the cruise. 15 i6 COPEPODS OF LAST CRUISE OF CARNEGIE Between stations 1 and 2 May 16, 1928; 37° 45' N, 53° 26' W; 49 species Depth of tow, m 50 100 Depth of tow, m 50 100 Acartia claiisii r Calanus minor f Calocalanus pavo r Candacia aethiopica r bispinosa f Centropages furcatus Clausocalanus arcuicornis r Clytemnestra scutellata Copilia denticulata Corycaeus anglicus crassiusculus c flaccus f limbatus r speciosus a typicus f Eucalanus attenuatus r elongatus f Euchaeta marina r Farranula carinata c curta gibbula rostrata c Lucicutia clausii flavicornis Macrosetella graciHs f Mecynocera clausi . , . . Megacalanus princeps. Microsetella norvegica. Miracia efferata Oithona plumifera similis spinirostris Oncaea curta media minuta similis venusta Pachos punctatum . . . . Paracalanus parvus. . . . Phaenna spinifera Rhincalanus cornutus. . nasutus Sapphirina darwinii . . . nigromaculata. . . . Scolecithricella minor. . Scolecithri.x danae Temora longicornis. . . . stylifera Undinula vulgaris This was the only occasion during the entire cruise when tows at all three depths were taken between stations. The vertical distribution of the species was 31 at the surface, 33 at 50 meters, and 32 at 100 meters, an exceptionally uniform dispersion. Twenty -one species (43 per cent) were confined to a single depth, and 19 were found at all three depths. This is the only cruise record for Sapphirina darwinii, and the only Atlantic record for Eucalanus attenuatus. Megacalanus prin- ceps, and Pachos punctaium. The presence of these isolated species and the unusual uniformity in vertical distribution is accounted for by the fact that these tows were taken during the night and not in the daytime. Station 2 May 18, 1928; 39° 06' N, 45° 41' W; bottom depth, 3900 m; 37 species Acartia longiremis 4 Calanus minor c Calocalanus pavo f Centropages chierchiae 3 Copilia denticulata r Corycaeus agilis r crassiusculus a - flaccus f speciosus a'' typicus f Eucalanus elongatus f Euchaeta marina r Farranula carinata a ^ Farranula curta f gibbula c rostrata c Macrosetella gracilis c Mecynocera clausi f Microsetella norvegica f Miracia efferata r Oithona plumifera f similis f Oncaea media c minuta c similis f Oncaea venusta c Paracalanus parvus c Phaenna spinifera r Pontellina plumata r Rhincalanus cornutus r nasutus a- Sapphirina angusta 2 auronitens r nigromaculata f Temora longicornis r stylifera c Undinula vulgaris r At this station only a surface tow was taken, with the temperature 20?5. the salinity 36.4 o/oo, and the hydrogen-ion concentration 8.23. The time was late in the forenoon and the sea was too rough to attempt the deeper tows. It must ha\e been also very dark and lowering, since the 2 Rhincalanus species were still at the surface, whereas they were usually confined to the deeper tows. This was the only record for Centropages chierchiae during the entire cruise. LISTS OF SPECIES BY STATIONS 17 Station 3 May 21, 1928; 44° 00' N. 36° 10' VV; bottom depth, 3738 m; 21 s[5ccies Depth of tow, 111 Temperature, ° Salinity, 0/00 50 100 Depth of tow. 111 50 100 15.5 14.9 13.6 Density (trtp) 26.6 26.9 27.4 36.0 35.9 35.8 Hydrogen-ion cone. (pH) 8.15 8.14 8.10 Acartia longiremis Calanus helgolandicus , . . . minor Candacia bispinosa Centropages f urcatus Ciausocalanus arcuicornis. Eucalanus elongatus Farranula carinata rostrata Labidocera nerii Mecynocera clausi Oithona pluniifera. . . setiger similis Oncaea minuta venusta Paracalanus parvus. . Rhincalanus nasutus. Sapphirina angusta. . nigromaculata. . Scolecithri.\ danae. . . Fifteen of the species (71 per cent) were confined to a single tow; there were 13 species at the surface, 11 at 50 meters, and 6 at 100 meters, the last being an exceptionally small number. Only 4 species were common, 1 Oithona and 2 Oncaea at the surface, and Scolecithrix at 50 meters. De\'elopment stages were abundant at each depth but could not be identified. Station 4 May 23, 1928; 44° 39' N, ir 06' W; bottom depth, 2439 m; 14 species Depth of tow, ni Temperature, °C Salinity, 0/00 50 100 Depth of tow, ni 50 100 14.6 14.3 13.4 Deiisitv (fftp) 26.7 27.1 27.4 35.9 36.0 35.8 Hydrogen-ion cone. (pH) 8.16 8.15 8.12 Calanus helgolandicus, . . . minor Calocalanus pavo Ciausocalanus arcuicornis. Drepanopus pectinatus. . . . Mecynocera clausi Oithona pluniifera Oithona similis c Paracalanus parvus f Pseudocalanus minutus r Sapphirina angusta r nigromaculata f stellata r Scolecithrix danae Seven species, or just half the entire number, were confined to a single tow, and the vertical distribution was also un- usually regular, with 8 species at each of the three depths. This is the only record for Drepanopus pectinatus, which was confined to the 100-meter tow. The development stages were found onlv in the 50-meter tow and could not be identified. i8 COPEPODS OF LAST CRUISE OF CARNEGIE Station 5 May 25, 1928; 43° 15' N, 31° 32' W; bottom depth, > 2719 m; 21 species Depth of tow, 111 Temperature, °C Salinity, o/oo 50 100 Depth of tow, m 50 100 15.0 14.6 13.5 Density (ertp) 26.6 27.0 27.4 35.8 36.0 35.8 Hydrogen-ion cone. (pH) 8.19 8.21 8.15 Acartia clausii f longiremis r Calanus helgolandicus r minor f Calocalanus pavo Centropages furcatus r Clausocalanus arcuicornis c Farranula carinata gibbula f Mecynocera clausi c Microsetella norvegica a Oithona pluniifera setiger similis Oncaea minuta venusta Pseudocalanus minutus. Rhincalanus nasutus. . . . Sapphirina angusta nigromaculata stellata The temperature varied only 1?5 in the upper 100 meters, and the salinity and hydrogen-ion concentration were nearly uniform. Fourteen species (66 per cent) were confined to a single tow, with 17 at the surface, 8 at 50 meters, and 8 at 100 meters. Dexelopment stages were again abundant at all three depths. Station 6 May 31, 1928; 50° 22' N, 13° 31' W; bottom depth, 2604 m; 21 species Depth of tow, m Temperature, °C Salinity, o/oo 50 100 Depth of tow, m 50 100 12.4 11.6 11.3 Density (ertp) 26.9 27.3 27.6 35.5 35.5 35.5 Hydrogen-ion cone. (pH) 8.15 8.12 8.08 Acartia clausii Calanus helgolandicus. . . . Centropages furcatus typicus Clausocalanus arcuicornis. Macrosetella gracilis Mecynocera clausi Metridia curticauda Microsetella nor\-egica. . . . rosea Oithona plumifera Oithona setiger similis Oithonina nana Oncaea minuta venusta Paracalanus parvus Pseudocalanus minutus. Rhincalanus cornutus. . . nasutus Sapphirina angusta The temperature dropped only 1° in the 100 meters, the salinity remained exactly the same, and the hydrogen-ion concentration diminished \ery slightly. There were 14 species in the surface tow, 7 in the 50-nieter tow, and 12 in the 100- meter tow. Thirteen of the species (62 per cent) were confined to a single depth and only 4 were found at all three depths. This is the only record of Centropages typicus for the entire cruise, a fact which, as this is a fairly common species, would seem to imply that it does not often come into the upper 100 meters. Here also is established one of the only two records for .Metridia curticauda: the second record was made during the surface tow of Jul> 11, between stations 6 and 7 (f). LISTS OF SPECIES BY STATIONS 19 Between stations 6 and 7 (a) June 2, 1928; 49° 30' N, 12° 00' \V; 22 species Tow Acartia clausii Calanus helgolandicus. , . . Candacia bispinosa Centropages furcatus hamatus Clausocalanus arcuicornis. Farranula carinata rostrata Macrosetella gracilis Metridia longa Microsetella norvegica. . . . Tow Oithona plumifera setiger similis Oithonina nana Oncaea media minuta venusta Paracalanus parvus Pseudocalanus minutus. Rhincalanus cornutus. . . nasutus These three tows were taken at the surface in the same June 2. A total of 22 species was obtained from all three tows, Iocalit\- successively at short internals during the night of and 12 (55 per cent) of these were confined to a single tow. Between stations 6 and 7 (b) June 3, 1928; 50° 00' \, 12° 30' \V; IS species Depth of tow, m 100 Depth of tow, m 100 Acartia clausii a Calanus helgolandicus r Metridia longa r Microsetella norvegica a Oithona plumifera f setiger r similis a Oithonina nana r Oncaea media f minuta c venusta f Paracalanus parvus a Pontella lobiancoi r Pseudocalanus minutus , c Sapphirina stellata r These two tow's were taken in the night, and it is worthy of note that every one of the species found at the 100-meter le\el was also present at the surface. There were 6 other species at the surface that were not found in the 100-meter tow. 20 COPEPODS OF LAST CRUISE OF CARNEGIE Between stations 6 and 7 (c) A. July 8, 1928; 54° 33' N, 6° 55' E B. July 10, 1928; 58° 50' N, 1° 48' E C. July 11, 1928; 59° 21' N, 1° 28' E 12 species Location of tow B Location of tow Acartia clausii a Calanus minor f Centropages hamatus a Clausocalanus arcuicornis f Eucalanus elongatus f Labidocera wollastoni r Metridia curticauda. . . . Microsetella norvegica. . Oithona plumifera Paracalanus parvus Pseudocalanus minutus. Temora longicornis The interval between June 8 and July 7 was spent in the harbors of Plymouth, England, and Hamburg, Germany. Three surface tows were taken in the North Sea on three different nights as recorded above. Onh^ 2 of the species were taken in all three tows, but on the other hand only 4 species were confined to a single tow. The total of 12 species for three night tows is exceptionally small and indicates a restricted copepod plankton. Depth of tow, m Temperature, °C Salinity, o/oo Station 7 July 13, 1928; 63° 20' N, 9° 25' W; bottom depth, 454 m; 11 species SO inn Depth of tow, m 8.9 8.2 8, 1 Density (a,i>) M.2 35.2 35.2 Hydrogen-ion cone (pH) 50 100 27.3 27.7 27.9 8.08 8.03 8.04 Acartia. clausii .... c a a r r c a c r c f Oithonina nana . . . r f f f a f . . . . c Oncaea venusta ... . . . r helgolandicus Microsetella norvegica Oithona plumifera similis Paracalanus parvus Pseudocalanus minutus c . . . c r c f This station was just east of the southern coast of Iceland. The temperature at the surface was very low and fell less than a degree in the 100 meters; the salinity was exactly the same at all three depths, and the hydrogen-ion concentration varied extremely little. The bottom depth is next to the smallest for the entire cruise. Only 3 of the species were confined to a single tow, and 6 were found in all three tows. This is the farthest north for Oncaea during the entire cruise, and this species may well have been brought into this vicinity by one of the ramifications of the Gulf Stream. LISTS OF SPECIES BY STATIONS 21 Station 8 July 15. 1928; 63° 30' N, 14° 41' \V; bottom depth, 1308 m; 12 species Depth of tow, m Temperature, °C Salinity, o/oo 50 100 Depth of tow, m 50 100 10.3 9.0 8.4 Density (crtp) 27.0 27.5 27.9 35.2 35.2 35.2 Hydrogen-ion cone. (pH) 7 . 93 7.95 7.95 Acartia clausii Calanus finmarchicus. . helgolandicus Clytemnestra rostrata. Gaidius brevispinus. . . Microsctella norvegica. Oithona plumifera setiger similis Oithonina nana Pontella lobiancoi Pseudocalanus minutus. This station was off the southern coast of Iceland but in In spite of the low temperature, many of the females in all very much deeper water than the preceding station. In the three tows were carrying ovisacs with the eggs nearly ready upper 100 meters the temperature varied 2°; the salinity and to hatch. This was the only record for Gaidius brevispinus, hydrogen-ion concentration were the same for all three depths, and the only Atlantic record for Clytemnestra rostrata. St.\tion 9 July 28, 1928; 62° 45' N, 25° 52' W; bottom depth, 882 m; 11 species Depth of tow, m Temperature, °C Salinity, o/oo 50 100 Depth of tow, m 50 100 11.1 8.3 7.5 Density (crtp) 26.8 27.5 27.9 35.1 35.1 35.1 Hydrogen-ion cone. (pH) 8.08 7.96 7.98 .^nomalocera patersonii . Calanus finmarchicus. . . helgolandicus minor Euchirella rostrata Microsetella norvegica. . Oithona plumifera. . . . similis Oithonina nana Scolecithricella ovata . Scolecithrix danae. . . . The temperature was still low at the surface, and fell 3° at 50 meters and another degree at 100 meters. Eleven species were obtained, of which 2 were found in all three tows and vhe other 9 (82 per cent) were confined to a single tow. This is one of the two Atlantic records for Anomalocera patersonii; the other was established at station 10, immediately follow- ing. In the 100-meter tow is found the only record for Sco- lecithricella ovata for the entire cruise. 22 COPEPODS OF LAST CRUISE OF CARNEGIE Station- 10 July 30, 1928: 59° 19' N. 34° 15' W; bottom depth. 3031 m; 8 species Depth of tow, m Temperature, °C Salinity, o/oo 50 100 Depth of tow, m 50 100 10.9 10.0 6.6 Density (aipi 26.7 27.1 27.9 34.9 34.9 35.0 Hydrogen-ion cone. (pH) 8.08 8.04 7.95 Anomalocera patersonii . Calanus finmarchicus. . . Euchaeta marina Microsetella norvegica. . Oithona siinilis spinirostris Oithonina nana Pseudocalanus minutus. The 8 species here recorded constitute the smallest yield for any regular station at which all three tows were taken, and with only one exception they were all confined to a single depth. Although the temperature at the 100-meter level was but 6?6, that tow as well as the other two contained hundreds of nauplii and metanauplii, of which those in the 100-meter tow must have been negatively phototropic. This is the second of the two Atlantic records for Anomalocera patersonii. Station 11 August 1, 1928; 58° 12' X, 35° 51' W; bottom depth, 2633 m; 10 species Depth of tow, m Temperature, °C Salinity, o/oo 50 Depth of tow, m 50 10.6 7.3 Density (' and hydrogen-ion concentration were high and nearly constant. The vertical distribution was very different: 14 species at the surface, 18 in the 50-meter tow, and 14 in the 100-meter tow. Nineteen species (60 per cent) were confined to a single tow, and onl>' 1 appeared in all three tows. This is another record in which every one of the species is well represented. Again the 3 species of Farra- nula and 1 species of Corycaeus appeared at the surface; the other 2 Corycaeus species with Oithona and Oncaea were confined to the two deeper tows. Station 17 August 15, 1928; 33° 42' N, 42° 21' \V; bottom depth, 4492 m; 28 species Depth of tow, m Temperature, °C Salinity, o/oo 50 100 Depth of tow, m 50 100 21.9 19.3 Density (irtp) 25.7 26.5 36.6 36.5 Hydrogen-ion concentration (pH) 8.27 8.22 Acartia longiremis Calanus helgolandicus minor c Candacia aethiopica r bispinosa r simplex f Centropages furcatus r violaceus r Clausocalanus arcuicornis f Corycaeus crassiusculus c speciosus c Euchirella brevis Farranula carinata gibbula f Farranula rostrata c f Haloptilus longicornis r Lubbockia squillimana r r Lucicutia clausii . . f flavicornis c c Macrosetella oculata r Microcalanus pusillus . . f Microsetella norvegica r Neocalanus gracilis f tenuicornis f Oithona similis . . c spinirostris . . c Oncaea media . . a venusta . . a This is the first station in the Sargasso Sea whose waters show a relatively high salinity. Eighteen species were found in the 50-meter tow and 15 in the 100-meter tow; only 5 species were found in both tows, 23 (82 per cent) being con- fined to one tow. The surface tow from this station was lost. Corycaeus and Farranula appeared in both the deeper tows, but Oithona and Oncaea were confined to the 100-meter tow. Candacia and Centropages were found only in the 50-meter tow. LISTS OF SPECIES BY STATIONS 27 Station 18 August 17, 1928; 29° 47' N, 40° 36' W; bottom depth, 4054 m; 33 species Depth of tow, m Temperature, °C Salinity, 0/00 50 100 Depth of tow, m 6.') 22..? 20.,? Density (fftp) 6.5 36.8 36.8 Hydrogen-ion cone (pH) 50 100 4.2 25.7 26.5 .23 8.24 8.21 Acartia longiremis Aetideus armatus Calanus helgolandicus. . minor Calocalanus pavo Candacia simplex Centropages furcatus. . . Corycaeus crassiusculus. pumiUis speciosus Euchirella brevis Farranula carinata gibbula rostrata Haloptilus longicornis. . . Lubbockia squillimana. . Lucicutia clausii c a c f f f f c f c a r a a f c c f r c Lucicutia tlavicornis. . . . longicornis Macrosetella graciHs. . . . Mecynocera clausi Microcalanus pusillus. . . M icrosetella norvegica. . Miracia efferata Oithona similis spinirostris Oncaea niinuta venusta Paracalanus parvus Ponteliina plumata Pseudocalanus minutus. Rhincalanus nasutus. . . . Sapphirina auronitens. . The temperature was quite high at the surface, but fell 30 per cent at the 100-meter level; the salinity and hydrogen- ion concentration were also high and remained practically unchanged. Eleven species were found at the surface, 15 at 50 meters, and 23 at 100 meters. Only 4 species were found in all three tows, and 21 (63 per cent) were confined to a single tow. This tow was taken late in the forenoon, and it is worthy of note that Acartia. Aetideus, Calocalanus, Candacia, Hal- optilus, Lubbockia. Ponteliina, and Rhincalanus were all confined to the 100-meter depth. If the tows had been taken at the usual time, earlier in the morning, probably some of these genera would have been found nearer the surface. 28 COPEPODS OF LAST CRUISE OF CARNEGIE Station 19 August 20, 1928; 24° 00' N, 39° 36' W; bottom deptli, 5392 m; 50 species Depth of tow, m Temperature, °C Salinity, o/oo 50 100 Depth of tow, in 50 100 26.6 25.2 22 3 Density (atp'l 24.3 2-.. 1 26.1 36.9 37.1 37.0 Hydrogen-ion cone. (pH) 8.34 8.27 8.25 Acartia longiremis Aetideus armatus Calanus helgolandicus. . . . minor Calocalanus pavo styliremis Candacia bispinosa norvegica simplex Centropages furcatus hamatus Clausocalanus arcuicornis. Clytemnestra scutellata. . . Copilia denticiilata Corycaeus crassiusculus. . . lautus pumilus speciosus Euchaeta marina Euchirella rostrata Farranula carinata gibbula rostrata Haloptilus longicornis ornatus c- Haloptilus plumosus I.uljbockia squillimana. . Lucicutia clausii (lavicornis longicornis Macrosetclla gracilis ociilata Mecynoccra clausi Megacalanus longicornis. Microcalanus pusillus. . . . Microsetella norvegica. . . Miracia cffcrata Oithona plumifera similis spinirostris Oithonina nana Oncaea media minuta venusta Paracalanus parvus Pseudocalanus niinutus. . Rhincalanus cornutus. . . . Sapphirina angusta auronitcns I'ndinula vulgaris c f r r f f r r a a r c a f f r r The temperature was still high at the surface and varied only 4° in the upper 100 meters; the salinity and hydrogen-ion concentration were very high and varied scarcely at all. The vertical distribution was more even, with 22 species at the surface, 29 at 50 meters, and 33 at 100 meters. Ten of these species were found in all three tows, and 26 (52 per cent) were confined to a single tow. This is the only Atlantic record for Ilaloplilus plumosus and the one locality where Lucicutia longicornis was present in sufficient numbers to be called common. Corycaeus, Farranula, Oithona, and Oncaea were each well represented in the surface tow. Station 20 August 22, 1928; 19° 13' N, 38° 28' W; bottom depth, 5626 m; 12 species Acartia longiremis r Calocalanus pavo f styliremis f Candacia bispinosa r Corycaeus dubius 2 speciosus f Farranula carinata ,1 gibbula f Farranula rostrata r Macrosctella gracilis f Oncaea minuta r Paracalanus parvus r The surface tow was the only one taken at this station, with temperature 26°, salinity 36.5 o/oo, and hydrogen-ion concen- tration 8.37. This station still shows a high temperature and high salinity. Although but 12 species are recorded, it must be remembered that this was a surface tow, for which 12 is a very fair record. If the two other tows had been taken there is no doubt that the total number of species recorded for this station would have been much larger. LISTS OF SPECIES BY STATIONS 29 Between stations 20 and 21 August 23, 1928; 16° 01' N, 37° 52' \V; 26 species Acartia longircmis. . . . Calanus minor propinquus Calocalanus pavo . . . . Candacia bispinosa. . . simplex Ccntropages furcatus. Corycaeus clausi speciosus Corycaeus typicus f Euchaeta marina f Euchirella brevis r Farranula carinata a gibbula f gracilis 3 rostrata f Luciciitia clausii a longicornis f Miracia efferata f Oncaea venusta a Paracalanns parvus c Pleuronianima xiphias r Pseudocalanus niinutus c Sapphirina auronitens f Scolecithrix danae a Undinula vulgaris a This surface tow was taken in the night. It contains 12 It thus furnishes good evidence of the nocturnal migration of species which were not found at either station 20 or station these species to the surface, and suggests that they may have 21, and is the onl>' Atlantic record for Pleuromamma xiphias. been present at the regular stations below the depths of tows. Station 21 August 24, 1928; 15° SO' X. 37° 56' W; bottom depth, 4977 m; 30 species Depth of tow, m Temperature, °C Salinity, 0/00 50 100 Depth of tow, m 50 100 5.5 24.4 21.0 Densitv () 22.8 24.9 26.8 35.2 36.0 35.6 Hydrogen-ion cone. (pH) 8.32 8.14 7.96 Acartia longiremis Aetideus armatus Calanus helgolandicus c minor propinquus Calocalanus pavo f styliremis r Candacia bispinosa norvegica pachydactyla f simplex f varicans Centropages furcatus r Clytemnestra scutellata Corycaeus crassiusculus speciosus f typicus Eucalanus elongatus Euchaeta marina Euchirella brevis Farranula carinata a gibbula c rostrata Haloptilus longicornis ornatus Heterorhabdus papilliger. Lucicutia clausii flavicornis Macrosetella gracilis Mecynocera clausi Megacalanus longicornis. Microcalanus pusillus. . , . pygmaeus Microsetella norvegica. . . Miracia eflferata Oithona similis spinirostris Oithonina nana Oncaea media minuta notopa venusta Paracalanus parvus Pareuchaeta grandiremis. Phaenna spinifera Pontellopsis regalis Pseudocalanus minutus. . Rhincalanus cornutus. . . . Scolecithrix danae Undinula vulgaris The temperature here dropped 4° in 50 meters from a high value at the surface, and 8° more at the 100-meter level. Fourteen species were found at the surface, 30 in the 50-meter tow, and 36 in the 100-meter tow. Twenty-three species (46 per cent) were confined to a single depth and only 4 were records, Corycaeus and Oncaea are each represented b>' a single species in the surface tow, but the former is better represented in the SO-meter tow and the latter becomes very abundant in the 100-meter tow. This last tow also contains the only record of Pareuchaeta grandiremis and one of two Atlantic records present in ail three tows. In contrast with the preceding of Microcalanus pygmaeus. LISTS OF SPECIES BY STATIONS 33 Station 25 September 3, 1928; 11° 02' N, 37° 06' VV; bottom depth, 4851 m; 31 species Depth of tow, 111 Temperature, °C Salinity, o/oo 100 Depth of tow, m 100 27.4 14.6 Density (' and h)drogen-ion concentration were also high and varied scarcely at all at the three depths. Twenty-six species were found at the surface, 25 in the 50-meter tow, and 27 in the 100-meter tow, an e.xceptionally uniform vertical distri- bution. Twenty species (45 per cent) were confined to a single depth and 10 were found at all three depths. All the species of Corycaeus and Farranula appeared at the surface, but only one species of Oncaea and none of Oithona. The two species of Acartia were as far apart as possible, one being confined to the surface tow and the other to the 100-meter tow. 36 COPEPODS OF LAST CRUISE OF CARNEGIE Station 29 September 13, 1928; 13° 16' N, 52° 13' W; bottom depth, 5068 m; 37 species Depth of tow, m Temperature, ° Salinity, o/oo 50 100 Depth of tow, m 27.5 27.1 23.1 Density (o-tp) 36.2 36.2 36.5 Hydrogen-ion cone (pH) 23.4 8.31 50 23.8 8.29 100 25.5 8.21 Calanus helgolandicus. . minor propinquus Calocalanus pavo styliremis Candacia bispinosa pachydactyla Centropages furcatus. . . Clytemnestra scutellata. Corycaeus crassiusculus. speciosus Euchacta marina Farranula carinata gibbula rostrata Haloptilus ornatiis spiniceps Lucicutia clausii Macrosctella gracilis. . . , Macrosetella oculata Mecynocera clausi Megacalanus longicornis. Microcalanus pusillus. . . , Microsetella norvegica. . . rosea Miracia eflferata (Jithona similis spinirostris Oncaea curta media minuta venusta. . Paracalanus parvus Phaenna spinifera Rhincalanus cornutus. . . . Scolecithrix danae Undinula vulgaris The drop from a high surface temperature was less than 0?5 at 50 meters and 4° at 100 meters; the salinity and hydro- gen-ion concentration were again practically unchanged and quite high. Twelve species were found at the surface, 23 at 50 meters, and 26 at 100 meters. Seventeen species (46 per cent) were confined to a single depth and only 4 were present at all three depths. The 50-meter tow furnished the only Atlantic record for Haloptilus spiniceps, and most of the Corycaeus species were conspicuous for their absence. Two species of Farranula, two of Oncaea, and Corycaeus crassiusculus were confined to the surface tow, and neither species of Oithona appeared there at all. LISTS OF SPECIES BY STATIONS 37 Station 30 September 15, 1928; 12° 54' N, 56° 15' W; bottom depth, 4703 m; 48 species Depth of tow, m Temperature, °C Sahnity, o/oo 50 100 Depth of tow, m SO 100 28.0 27.7 24.1 Density (crip) 23.2 23 . 5 25.1 36.0 36.0 36.3 Hydrogen-ion cone. (pH ) 8.30 8.30 8.26 Calanus helgolandicus. . minor propinquus Calocalanus pave styliremis Candacia bi.spinosa pachydactyla simplex Centropages furcatus. . . Clytemnestra scutellata. Corycaeus agihs crassiusculus dubius lautus limbatus pumilus speciosus Eiichacta marina Farranula carinata gibbula rostrata Haloptiius ornatus Luciciitia clausii flavicornis Macrosetella gracilis. . . . oculata Mecynocera clausi Microcalanus pusillus. . . Microsetella norvegica. . rosea Oithona hebes plumifera similis spinirostris Oncaea curta media minuta notopa subtilis tcnella venusta Paracalanus parvus Phaenna spinifera Pontellopsis perspicax. . Pseudocalanus minutus. Rhincalanus cornutus. . . Scolecithrix danae Undinula vulgaris The temperature at all three depths was high and showed only 4° variation; the salinity and hydrogen-ion concentration were also high and \aried extremely little. Twenty-two species were taken at the surface, 21 at 50 meters, and 28 at 100 meters. Thirty-two species (66 per cent) were each confined to a single depth and 7 were found at all three depths. The 100-meter tow contained the only record for Oithona hebes and the surface tow one of two Atlantic records for Oncaea subtilis. Corycaeus, Farranula, and Oncaea all appeared in goodly numbers at the surface, but no one of the four Oithona species was found there, two of them being confined to the 50-meter tow and the other tw-o to the 100-meter tow. 38 COPEPODS OF LAST CRUISE OF CARNEGIE Station 31 October 3, 1928; 14° 46' N, 63° 26' W; bottom depth, 1635 m; 52 species Depth of tow, m Temperature, Salinity, o/oo 50 100 Depth of tow, m 50 100 28.5 28.2 23.4 Density (o-tp) 21.7 22.8 25.4 34.4 35.3 36.4 Hydrogen-ion cone. (pH) 8.27 8.23 8.19 Acartia longiremis Aetideus armatus Calanopia americana Calanus helgolandicus. . . . minor Calocalanus pavo Candacia bispinosa norvegica pachydactyla simplex Clausocalanus arcuicornis. Clytemnestra scutellata. . . Copilia denticulata Corycaeus anglicus clausi crassiusculus flaccus minimus speciosus typicus Euchaeta marina Farranula carinata curta gibbula rostrata Haloptilus ornatus c f c f c c f c f Labidocera nerii Lubbockia squillimana. . Lucicutia flavicornis. . . . grandis Macrosetella gracilis. . . . Mecynocera clausi Microcalanus pusillus . . Microsetella norvegica. . rosea Oithona plumifera setiger similis spinirostris Oithonina nana Oncaea minuta tenella venusta Paracalanus parvus Phaenna spinifera Pontellina plumata Pseudocalanus minutus. Rhincalanus cornutus. . . nasutus Sapphirina auronitens. . Scolecithrix danae Temora stvHfera r c c r a r f c c f r a c f c a a f r c f f A high surface temperature, with 5° drop in 100 meters; a low surface sahnity, rising 2 points in 100 meters. Nine species only were found at the surface, 34 at 50 meters, and 38 at 100 meters. Twenty-seven species (52 per cent) were each confined to a single tow and only 4 were present in all three tows. The 100-meter tow contained the only record for Lucicutia grandis and the 50-meter tow one of two Atlantic records for Corycaeus clausi. The small species of Corycaeus, Farranula, Oithona, and Oncaea were especially abundant in the two deeper tows. Again none of the 4 Oithona species, only 1 of the 4 Farranula species, and 1 of the 3 Oncaea species appeared at the surface. LISTS OF SPECIES BY STATIONS 39 Station 32 October 5, 1928; 15° 18' N, 68° 11' W; bottom depth, 4566 m; 54 species Depth of tow, m Temperature, °C Sahnity, o/oo 50 100 Depth of tow, m 50 100 28.0 27.2 22 2 Density (o-tp) 23.1 23.5 25.6 35.0 35.') ,?6.3 Hydrogen-ion cone. (pH) 8.23 8.24 8.15 Acartia longiremis Aetideus armatus Calanopia aniericana elliptica Calanus helgolandicus. . . . minor propinquus Calocalanus pavo Candacia bispinosa norvegica pachydactyla Centropages furcatus haniatus Clausocalanus arcuicornis. Clytemnestra scutellata. . . Copilia denticulata Corycaeus anglicus crassiusculus dubius furcifer lautus minimus speciosus Eucalanus elongatus Euchaeta marina Farranula carinata rostrata I4aloptilus ornatus Labidocera wollastoni r Lucicutia flavicornis Macrosetella gracilis f f Mecynocera clausi Microcalanus pusillus . . f Microsetella norvegica f f Oithona plumifera r similis . . f spinirostris Oithonina nana . . f Oncaea conifera 2 media r minuta c f subtilis . . r venusta c a Paracalanus parvus c a Phaenna spinifera Pontella atlantica r lobiancoi r Pontellina plumata r Pseudocalanus minutus f a Rhincalanus nasutus c Scolecithrix danae . . r Temora longicornis r f stylifera f f Undinula vulgaris A high temperature at the surface and at SO meters, with a drop of more than 5° at 100 meters; the saiinit>' and hydrogen- ion concentration \-arying \'ery little. Twenty-nine species were found at the surface, 24 at 50 meters, and 34 at 100 meters. Thirteen species were found at all three depths, and 34 (63 per cent) were each present in but one tow. The surface tow contained the only Atlantic record of Calanopia elliptica, and the SO-meter tow the only Atlantic record of Corycaeus furcifer. Corycaeus, Farranula, and Oncaea were each well represented in the surface tow, with only one Oithona species. 40 COPEPODS OF LAST CRUISE OF CARNEGIE Station 33 October 8, 1928; 13° 37' X, 76° 22' \V; bottom depth, 4039 ni; 27 species Depth of tow, m Temperature, °C Salinity, o/oo 50 100 Depth of tow, m 50 100 28.1 22.3 Density (o-ipi 23.4 25.7 36.2 36.4 Hydrogen-ion concentration fpHj 8.24 8.18 Calanus helgolandicus . . minor propinquus Candacia bispinosa Corycaeus crassiusculus. speciosus Eucalanus elongatus. . . . Euchaeta marina Farranula carinata gibbula rostrata Lubbockia squilhmana. . Lucicutia flavicornis. . . . Macrosetella graciUs. . . . r f r f r r f f f r a r c Mecynocera clausi r M icrosetella norvegica f c rosea . . r Oithona pluniifera r r similis r Oncaea minuta f venusta c c Paracalanus parvus r Pseudocalanus minutus f Rhincalanus nasutus . . r Temora longicornis a c stylifera f r Undinula vulgaris . . r Vessel rolling and pitching badly, occasioning loss of surface tow. Eighteen species were found in the 50-meter tow and 17 in the 100-nieter tow; 8 species were found at both depths, and 19 (70 per cent) were each present in but one tow. LISTS OF SPECIES BY STATIONS 41 Station 34 October 9, 1928; 11° 18' N, 78° 34' \V; bottom depth, 3536 m; 48 species Depth of tow, m Temperature, °C Salinity, 0/00 28.5 35.8 50 100 Depth of tow, m 50 100 24. q 20.5 Density {(r,p) 22 9 24.7 26.3 36.5 36.6 Hydrogen-ion cone. (pH) 8.28 8.21 8.16 Acartia clausii Aetideus armatus Calanus hclgolandicus. . . . minor Calocalanus pavo Candacia bispinosa norvegica Clausocalanus arcuicornis. Clytemnestra scutellata. . . Copilia denticulata Corycaeus agilis crassiusculus speciosus Eucalanus elongatus Euchaeta marina Farraniila carinata gibbula rostrata Haloptilus ornatus Lubbockia squillimana. . . . Lucicutia flavicornis Macrosetella gracilis oculata Mecvnocera clausi Megacalanus longicornis . . r Microsetella norvegica c f rosea . . r Oithona plumifera c c similis . . c spinirostris . . r Oithonina nana . . r Oncaea minuta r r tenella r venusta a c Paracalanus parvus . . r Phaenna spinifera . . c Pontella securifer r Pontellina plumata . . r Pseudocalanus minutus f f Rhincalanus cornutus . . c nasutus . . c Sapphirina angusta scarlata . . r Scolecithrix danae . . c Spinocalanus abyssalis Temora longicornis r r stylifera c r Undinula vulgaris . . c The temperature, high at the surface, dropped 4° at SO meters and 4° more at 100 meters; the salinity increased and the hydrogen-ion concentration diminished downward, each by small amounts. Si.xteen species were found at the surface, 40 at SO meters, and 35 at 100 meters. Eleven species were found at all three depths, and 16 (33 per cent) were each present in but one tow. Tlie surface tow contained the only Atlantic record of Pontella securifer and the SO-meter tow the only Atlantic record of Sapphirina scarlata. .\ll the species of Corycaeus, Farranula, and Oncaea were well represented at the surface, but only one of the three Oithona species appeared there. 42 COPEPODS OF LAST CRUISE OF CARNEGIE Station 35 October 26, 1928; 6° 32' N, 80° 04' W; bottom depth, 3583 m; 96 species Depth of tow, m Temperature, °C Salinity, o/oo Volume of tow, cm' 50 100 Depth of tow, m 50 100 27.4 16.8 14.4 Density (-. This is the first of a series of four night tows, three at the surface and one at 50 meters, taken when the vessel was becalmed between stations 35 and 36. It yielded 65 species of copepods, making it the largest surface tow for the entire cruise. The present tow contains 1 1 species not found in the other three, and lacks 36 species that were found in one or more of those three, a fact which emphasizes the diversity of surface distribution. It contains the only record for Pandarus sinuatus, a species parasitic on sharks and rays; a single young female was taken while swimming freely in the tow. The record shows only two species of Canda- cia but contains a long series of Corycaeus and Oncaea, three of the latter being especially abundant. 44 COPEPODS OF LAST CRUISE OF CARNEGIE Between stations 35 and 36 (b) October 27, 1928; 5° 22' N, 79° 59' W; 64 species Acartia danae c negligens c Acrocalanus gibber c gracilis c longicornis f Aegisthus spinulosus 1 Calanus minor a propinquus f Calocalanus pavo c plumulosus 2 Candacia bipinnata 2 bispinosa ^ curta 1 norvegica 1 pachydactyla 2 simplex f Canthocalanus pauper f Centropages calaninus 1 furcatus a Clausocalanus arcuicornis f furcatus 2 Clytemnestra rostrata 1 Corycaeus agilis f catus 2 clausi r crassiusculus f flaccus f giesbrechti 3 lautus 5 limbatus f pacificus 4 pumilus c speciosus c Eucalanus elongatus 2 monachus c Euchaeta marina r Farranula carinata a concinna f gibbula c rostrata a Labidocera acuta 2 dctruncata c Lucicutia clausii 2 Macrosetella gracilis c Microcalanus pusillus 4 pygmaeus f Microsetella norvegica 1 rosea r Neocalanus gracilis 4 Oithona similis 3 Oithonina nana 2 Oncaea curta f media c minuta a similis f subtilis f venusta a Paracalanus parvus r Pontellina plumata a Pseudocalanus minutus f Scolecithricella marginata 19 Temora discaudata f Undinula caroli 2 vulgaris f Volume of tow, 150 cm'; time, 7''30"' to 9''20" p.m.; length, 0.6 mile; surface only. This is the second of the nocturnal surface tows, and contains 64 species, only 1 less than the preceding tow. Thirteen of these species were not present in either of the other tows, and conversely those tows contained 28 species which are not found here, again emphasizing di\ersity. Here at the surface in the night appeared 6 species of Candacia, 3 of which were not found at any depth in the daytime at either station 35 or 36, and again there are long series of Corycaeus and Oncaea. Centropages furcatus and Pontellina plumata were exceptionall>- abundant in this tow, their normal representation being only a few individuals. ^ LISTS OF SPECIES BY STATIONS 45 Between stations 35 and 36 (c) October 28, 1928; 4° 16' N, 79° 37'-47' W; 72 species Depth of tow, m \'olume of tow, cm' U)0 50 48 Depth of tow, ni Length of tow, miles 1.0 50 3.2 Acartia danae negligens Acrocakmus gibber gracilis longicornis Aegisthus spinulosus Calanus minor Calocalanus pavo plumulosiis Candacia bispinosa pachydactyla simplex truncata Canthocalanus pauper. . . . Centropages calaninus. . . . furcatus violaccus Clausocalanus arcuicornis. furcatus Clytcmnestra scutellata. . . Copilia quadrata Corycaeus agilis clausi crassiusculus dubius lautus limbatus pumilus Eucalanus attenuatus crassus elongatus monachus Euchaeta acuta marina Farranula carinata concinna Farranula curta gibbula rostrata Gaetanus minor, juv. . . . Labidocera acuta detruncata Lubbockia squillimana. . Macrosetella gracilis. . , . Mecynocera clausi Microcalanus pusillus. . . pygmaeus Microsetella rosea Neocalanus gracilis robustior Oithona attenuata brevicornis plumifera similis spinirostris Oncaea curta media minuta subtilis venusta Paracalanus aculeatus. . parvus pygmaeus Pleuromamma gracilis. . Pontellina plumata Pseudocalanus minutus. Rhincalanus cornutus. . . Sapphirina angusta ovatolanceolata . . . . Temora discaudata stylifera Undinula vulgaris c f Id' 2 1 f c c r f 1 4 3 f c c a This record includes the tliird of the nocturnal surface tows and an additional 50-meter tow; time, 9''40"' p.m. to 12''50'" A.M. The former contains only 2 species not found in the other surface tows, but it does not contain 50 species that were found in them, thereby e\en surpassing them in diver- sity. Forty-one species were found in the surface tow and 58 in the 50-meter tow; 27 species were present in both tows, and 45 were each confined to a single tow. Nocturnal tows at lower levels yield interesting comparisons with surface hauls. The volume of the 1-mile surface tow is three and one-third times that of the 3-mile 50-meter tow, and yet the latter con- tained 17 more copepod species than the former. 46 COPEPODS OF LAST CRUISE OF CARNEGIE Station- 36 October 30, 1928; 2° 54' N, 80° 02' W; bottom depth, 4880 m; 75 species Depth of tow, m Temperature, °C SaHnity, o/oo Volume of tow, cm^ 50 100 Depth of tow, m 50 100 26.5 18.5 14.4 Density (fftp) 20.3 25.0 26.4 31.6 34.5 34.9 Hydrogen-ion cone. (pH) 8.23 8.03 7.85 198 86 32 Length of tow, miles 0.5 0.8 0.8 Acartia neghgens Acrocalanus gibber gracilis monachus Aetideus armatus Amallothrix obtusifrons. . . Calanus minor Calocalanus pavo Candacia simplex truncata Canthocalanus pauper. . . . Centropages calaninus. . . . furcatus Clausocalanus arcuicornis. furcatus CopiUa denticulata Corycaeus agiHs andrewsi crassiusculus dubius lautus limbatus pumilus robustus speciosus Euaetideus giesbrechti. . . . Eucalanus crassus elongatus monachus Euchaeta acuta marina Euchirella intermedia pulchra Farranula carinata gibbula gracilis rostrata Haloptilus acutifrons 1 1 5 4 f 2 f 1 Icf c c 2 Haloptilus longicornis. . . . ornatus plumosus Heterorhabdus papilliger. Labidocera detruncata. . . Lubbockia aculeata Lucicutia clausii flavicornis Macrosetella gracilis Microcalanus pusillus. . . . pygmaeus Microsetella rosea Neocalanus gracilis tenuicornis Oithona attenuata plumifera similis spinirostris Oncaea anglica curvata media mediterranea minuta similis venusta Paracalanus parvus Pseudocalanus minutus. . Rhincalanus cornutus. . . . nasutus Sapphirina auronitens. . . Scolecithricella bradyi . . . Scolecithrix danae Temora discaudata stylifera Undinula caroli darwinii vulgaris 2 Icf 1 1 f 2 19 Forty-four species were present at the surface, 37 in the 50- meter tow, and 49 in the 100-meter tow. The surface tow of 0.5 mile yielded more than six times the volume of plankton that was obtained in the 100-nieter tow of 0.8 mile, but the latter contained 5 more copepod species than the former. The three tows totaled 75 species, of which 38 (51 per cent) were each confined to a single depth, and 15 were found at all three depths. LISTS OF SPECIES BY STATIONS Station 37 November 1, 1928; 5° 59' N, 82° 56' W; bottom depth, 3324 m; 88 species 47 Depth of tow, m Temperature, °C Sahnity, o/oo Volume of tow, cm" SO 100 Depth of tow, m SO 100 27.1 19.8 15.1 Density (o-tp) 20.2 24.7 26.3 31.6 ,U.5 34.9 Hydrogen-ion cone. (pH) 8.28 8.00 7.82 .'24 ,12 64 Length of tow, miles 0.8 1.0 1.0 Acartia danae . . 2 negligens f Acrocalanus gibber f gracilis c f longicornis f 1 Aetideus armatus Calanus minor c c Calocalanus pavo c Candacia bispinosa 2 pachydactyla 4 simplex c Canthocalanus pauper c f Centropages ealaninus 2 2 furcatus . . 1 Clausocalanus arcuicornis f furcatus a c Clytemnestra scutellata Copilia denticulata 3 1 Corycaeus agilis f andrewsi 4 crassiusculus 4 dubius c 2 lautus 2 limbatus 4 pacificus 2 r pumilus f 2 robustus 2 speciosus f typicus f Danodes plumata, n. gen. and n. sp. 3 9 Euaetideus giesbrechti Eucalanus crassus elongatus . . f monachus 3 c mucronatus Euchaeta acuta 2 marina f f Farranula carinata a a gibbula a c gracilis f rostrata f Gaetanus miles Haloptilus longicornis Heterorhabdus papilliger Labidocera detruncata . . . Lubbockia aculeata squillimana Lucicutia bicornuta clausii flavicornis Mecynocera clausi Microcalanus pusillus. . . . pygmaeus Microsetella rosea Miracia efTerata Neocalanus gracilis tenuicornis Oithona attenuata pluniifera similis spinirostris vivida Oithonina nana Oncaea curta curvata media minuta similis subtilis venusta Paracalanus parvus pygmaeus Phaenna spinifera Pleuromamma gracilis. . . Pontella lobiancoi Pontellina plumata Pseudocalanus minutus. . Rhincalanus cornutus. . . . Sapphirina auronitens. . . nigromaculata Scolecithricella abyssalis. bradyi minor Scolecithrix danae Temora discaudata Undinula darwinii vulgaris \ ettoria granulosa S 1 9 f 29 2 4 2 c a 2 a The temperature dropped 44 per cent in the upper 100 meters; the salinity rose 3 points and the density 6 points. Forty-nine species were taken at the surface, 42 in the 50- meter tow, and 55 in the 100-meter tow, but the volume of the surface tow was seven times that of the 50-meter tow and three and a half times that of the 100-meter tow although its length was 20 per cent less than that of either of the others. Forty-four species (50 per cent) were each confined to a single tow, and 15 were found in all three tows. The 3 speci- mens of Oithona vivida taken in the two deeper tows are the only ones obtained during the cruise. Numerals are less fre- quent in the abundance records, but there are still 6 species each of which is represented by a single specimen. Corycaeus, Oithona, and Oncaea were each well represented by species in all three tows, and the surface tow contained 3 specimens of the new genus Danodes. COPEPODS OF LAST CRUISE OF CARNEGIE Station 38 November 3, 1928; 3° 46' N, 81° 37' W; bottom depth, 2264 m; 86 species Depth of tow, 111 Temperature, °C SaHnity, o/oo Volume of tow, cm' 50 100 Depth of tow, m 50 100 26.4 21.3 15.6 Density (irtp) 21.3 24.1 26.2 32.8 34.3 34.9 Hydrogen-ion cone. (pH) 8.33 8.14 7.91 48 70 150 Length of tow, miles 0.8 2.5 2.5 Acartia danae negligens Acrocalanus gracilis longicornis Aetideus armatus Calanus minor tonsus Calocalanus pavo pluniulosus Candacia bispinosa simplex truncata Canthocalanus pauper Centropages furcatus Clausocalanus arcuicornis furcatus Clytemnestra scutellata Copilia denticulata Corycaeus agilis crassiusculus dubius flaccus lautus limbatus puniilus speciosus Danodes plumata, n. gen. and n. sp. Euaetideus bradyi giesbrechti Eucalanus attenuatus crassus elongatus monachus mucronatus Euchaeta acuta marina Euchirella brevis pulchra Farranula carinata curta gibbula gracilis Haloptilus longicornis f 3 3 4 2 19 Haloptilus pluniosus Labidocera detruncata. . . . Lubbockia aculeata squillimana Lucicutia clausii flavicornis longicornis Macrosetella gracilis Mecynocera clausi Megacalanus longicornis. . princeps Microcalanus pygniaeus. . . Microsetella rosea Neocalanus gracilis robustior Oithona attenuata plumifera similis spinirostris Oncaea conifera curta media minuta similis venusta Paracalanus parvus pygniaeus Phaenna spinifera Pontellina plumata Pseudocalanus minutus. . . Rhincalanus cornutus nasutus Sapphirina nigromaculata . Scolecithricella abyssalis . . bradyi minor Scolecithrix danae Spinocalanus abyssalis. . . . Temora discaudata Undinula caroli darwinii vulgaris \'ettoria granulosa The drop in temperature here was 40 per cent, the rise in salinity 2 points, and the rise in density 5 points. The 50- meter tow, with a length three times that of the surface tow, had a volume only one-half larger, and yielded half as many more species. The 100-meter tow had twice the volume of the 50-meter tow, with the same length, and yielded almost twice as many species. There were 25 species at the surface, 40 in the SO-meter tow, and 72 in the 100-meter tow. Forty-six species (53 per cent) were each confined to a single tow and 11 were present in all three tows. The 1 Aetideus and 2 Euaetideus species were restricted to the 100-meter tow; the 3 Candacia species, 4 of the 5 Eucalanus species, the 4 Oithona species, and the 2 Rhincalanus species appeared only in the two deeper tows. Corycaeus and Oncaea were well represented with species which were divided among all three tows. One specimen of the new genus Danodes was taken at the surface. LISTS OF SPECIES BY STATIONS Station 39 November 6, 19iS; if 52' X, 81° 14' W; iM.u.mi depth, 3200 m; 85 species 49 Depth of tow, m Temperature, °C Salinity, o/oo \'olunie of tow, cm' 50 100 Depth of tow, m 50 100 24.8 16.3 14.0 Density (cTtp) 21.8 25 . 6 26.6 32. y 34.6 34.9 Hydrogen-ion cone. (pH) 8.24 7.92 7.88 336 48 38 Length of tow, miles 1.1 1.1 1.1 Acartia negligens Acrocalanus gibber gracilis monachus Aegisthus spinulosus Aetideiis armatus Amallothri.x obtusifrons. . . Calanus minor Calocalanus pavo Candacia bispinosa ciirta pachydactyla simplex truncata Canthocalanus pauper. . . . Centropages furcatus Clausocalanus arcuicornis. furcatus Clyteninestra rostrata . . . . scutellata Corycaeus agilis andrewsi crassiusculus lautus limbatus speciosus Euaetideus bradyi giesbrechti Eucalanus attenuatus crassus elongatus monachus mucronatus Euchaeta acuta marina Euchirella breyis rostrata Farranula carinata curta gibbula gracilis Haloptilus longicornis. ... ornatus lleterorliabdus papilliger spinifrons Lucicutia clausii flavicornis longicornis Macrosetella gracilis Microcalanus pusillus f pygmaeus f Microsetella rosea 2 Miracia etferata 4 Neocalanus gracilis 2 robustior Oithona attenuata plumifera siniilis spinirostris Oncaea conifera curta media c minuta a similis subtilis venusta a Pachyptilus abbreyiatus, juv Paracalanus paryus c pygmaeus 4 Phaenna spinifera Pseudocalanus minutus Rhincalanus cornutus nasutus Sapphirina auronitens 3 nigromaculata 1 Scolecithricella abyssalis bradyi marginata minor, juv 1 cT Scolecithri.x danae '. Temora discaudata c stylifera 1 Undinula darwinii f vulgaris 3 X'ettoria granulosa 1 3 c 2 1 f c f f r r 4 1 2 1 4 f 2 r c c 2 f c a a 2 1 a a Id' f r f f f 3 f 3 2 1 There was a drop in temperature of 43 per cent between the surface and the 100-meter level, a rise of 2 points in salinity, and a slight diminution in hydrogen-ion concentration. The frequent numerals in the abundance records still indicate a very small number of specimens for many of the species. Candacia, Corycaeus. Eucalanus, and Oncaea were each repre- sented by 5 to 7 species, although the number of individuals in all except Oncaea was \ery small. The SO-meter tow con- tained the only record for Pachyptilus abbreviatus, a young male not fully developed. Forty-five species (53 per cent) were each confined to a single depth and 14 were taken at all three depths. More specimens of Lucicutia longicornis were captured here in the 100-meter tow than at any other locality. The 1 Aetideus, 2 Euaetideus, and 2 Rliincalanus species were found only in the deepest tow, and the 5 Candacia species were confined to the two deeper tows. 50 COPEPODS OF LAST CRUISE OF CARNEGIE Station 40 November 8, 1928; 1° 32' S, 82° 16' W; bottom depth, 1344 m; 90 species Depth of tow, m Temperature, °C Salinity, o/oo \ olume of tow, cm' 50 100 Depth of tow, m 50 100 22.2 15.3 13.9 Density (o-tp) 23.2 26.0 26.6 33.7 34.9 34.9 Hydrogen-ion cone. (pH) 8.21 7.87 7.85 288 70 62 Length of tow, miles 1.2 1.0 1.0 Acartia negligens Acrocalanus gibber gracilis longicornis Aegisthus spinulosus Aetideus armatus Amallothrix obtusifrons. . . Calanus minor tonsus Calocalanus pavo styliremis Candacia bispinosa curta pachydactyla Canthocalanus pauper. . . . Centropages furcatus Clausocalanus arcuicornis. furcatus Clytemnestra scutellata. . . Copilia denticulata Corycaeus agilis andrewsi crassiusculus dubius limbatus ovalis pacificus pumilus robustus speciosus Euaetideus giesbrechti. . . . Eucalanus elongatus monachus mucronatus subtenuis Euchaeta acuta marina Euchirella brevis curticauda pulchra rostrata Farranula carinata curta gibbula gracilis 1 9 1 2 a f f c 2 19 c Id' 19 1 2 3 Farranula rostrata 2 Haloptilus longicornis .. .. 4 ornatus . . . . 19 Heterorhabdus papilliger . . 1 Heterostylites longicornis . . 1 3 Labidocera acuta f detruncata f Lucicutia clausii . . . . 1 flavicornis Macrosetella gracilis Microcalanus pusillus pygmaeus Microsetella rosea Miracia efferata Neocalanus gracilis Oithona brevicornis plumifera similis spinirostris Oithonina nana Oncaea conifera curta curvata media minuta venusta Onchocalanus nudipes, n. sp Paracalanus parvus pygmaeus Pareuchaeta tumidula Phaenna spinifera Pontella danae 2 Pontellina plumata c Pontellopsis lubbockii f regalis, juv 2 Pseudocalanus minutus . . f f Rhincalanus cornutus . . 2 nasutus . . a a Sapphirina auronitens 2 2 1 opalina . . 1 Scolecithricella bradyi 1 2 4 Scolecithrix danae . . 2 4 Temora discaudata a . . 2 Undinula darwinii f f f vulgaris f 4 1 4 1 f c f f c f f f f 2 1 4 3 f f c f c c 1 3 f 2 2 5 c 3 f 5 2 4 c c a c a a a 29 c c 19 c 4 c f The drop in temperature was almost 40 per cent in the 100 meters, the rise in saiinit>' was only 1 point, and the hydrogen- ion concentration diminished a little. The volume of the tow at the surface was four times that at each of the two greater depths, with only a 20 per cent increase in its length. The number of species in this surface tow was also a little larger than in either of the other tows, which is the reverse of the usual proportion. Forty species (44 per cent) were each con- fined to a single depth and 24 were found at all three depths. The species are exceptionally well distributed vertically, with 58 at the surface, 51 at 50 meters, and 55 at 100 meters. About half of the abundance records are for 5 individuals or less, 24 of them being single specimens. The surface tow contains the only record for Pontellopsis lubbockii, the 50-meter tow the only record for Pareuchaeta tumidula, and the lOO-meter tow one of the few records for Eucalanus subtenuis. LISTS OF SPECIES BY STATIONS 51 Station 41 November 10, 1928; 1° 37' S, 86° 58' \V; bottom depth, 2568 m; 74 species Depth of tow, m Temperature, °C Salinity, 0/00 \'ohinie of tow, cm' 50 100 Depth of tow, m 50 100 20.4 14.6 14.5 Density (o-tp) 24.0 26.3 26.5 34.1 35.0 35.0 Hvdrogen-ion cone. (pH ) 8.11 7.94 7.92 224 54 86 Length of tow, miles 2.0 1.7 1.7 Acarlia clanae Acrocalanus gibber gracilis longicornis Aegisthus spinulosus Calanus tonsus Calocalanus pavo styliremis Canthocalanus pauper. . . . Centropages furcatus Clausocalanus arcuicornis. furcatus Clytemnestra scutellata. . . Corycaeus agilis crassiusculus pumilus speciosus typicus Eucalanus attenuatus crassus elongatus monachus mucronatus Euchaeta acuta marina Euterpina acutifrons Farranula carinata curta gibbula gracilis Gaidius tenuispinus Haloptilus longicornis ornatus Ik'terorhabdus papilliger. . Labidocera acuta detruncata. juv I.ubbockia squillimana. . . . Lucicutia clausii flavicornis longicornis Microcalanus pusilius. . . pygmaeus Microsetella rosea Neocalanus gracilis tenuicornis Oithona attenuata plumifera similis spinirostris Oncaea conifera curta media minuta subtilis tenella venusta Paracalanus parvus Phaenna spinifera Pleuromamma gracilis. . Pontella danae Pontellina plumata Pseudocalanus minutus. Rhincalanus cornutus. . . nasutus Sapphirina auronitens. . opalina Scolecithricella bradyi . . Scolecithrix danae .Spinocalanus abyssalis. . Temora discaudata longicornis Undinula caroli darwinii \'ettoria granulosa 29 f Id' r 1 The temperature dropped 6° in the 100 meters, the salinity rose 1 point, and the h\drogen-ion concentration diminished a little. The volume of the surface tow was four times that of the 50-meter tow and two and a half times that of the 100- meter tow, although its length was only one-sixth greater. Fort\-se\en species (63 per cent) were each confined to a single depth and 12 were present at all three depths. Corycaeus, Eucalanus. and Oncaea were each again represented by 5 to 7 species, but Candacia was entirely absent. The vertical dis- tribution was 36 species at the surface, 34 in the SO-meter tow, and 44 in the 100-meter tow. Both Rhincalanus species were present at all three depths, instead of being confined to the deeper tows as usual. Three of the Farranula species appeared only in the surface tow, and 1 species was equally di\ided between the surface and the 100-meter tow. Sim- ilarly, 2 of the Acrocalanus species were confined to the surface tow and the third species was confined to the 100- meter tow. Of the Corycaeus species, 1 appeared only in the two deeper tows, 1 appeared at all three depths, 2 were con- fined to the surface tow, and 1 to the 100-meter tow. Similar differences can be found among the Oithona and Oncaea species. A careful study of any of these station records where a large number of species of the same genus are present sup- ports the suggestion of Rose (see p. 13) that the adaptation of copepods to light varies with each species. It will also go far toward removing opposition to his further suggestion that possibly such adaptation varies with each individual. The inconsistencies which so frequently confront us can hardly be explained on any other assumption. 52 COPEPODS OF LAST CRUISE OF CARNEGIE Between stations 41 and 42 November 12, 1928; 1° 12' S, 91° 27' \V; 19 species Calanus propinquiis 3 Corycaeus agilis 2 catus 1 pumilus r typicus r Eucalanus crassus 2 Farranula gibbula 1 Parranula gracilis f rostrata c Labidocera acuta 3 Microsetella rosea r Miracia efferata 2 Neocalanus gracilis r Oithona similis f Oncaea venusta f Paracalanus parvus a Pseudocalanus minutus r Undinula darwinii 2 vulgaris f This nocturnal surface tow was less productive than those between stations 35 and 36, and yielded only 19 species, half of which were represented b>' 3 specimens or less. Calanus propinqiius was not present at station 41 and only in the 100- meter tow at station 42. Two of the Corycaeus species, agilis and lypicus, were confined to the deeper tows at stations 41 and 42, and catus did not appear at either of those stations; nor did Miracia efferata and Undinula vulgaris. Station 42 November 13, 1928; 1° 32' S, 93° 10' \V; bottom depth, 3539 m; 74 species Depth of tow, m Temperature, ° Salinity, o 'oo X'olume of tow. 50 100 Depth of tow, m 50 100 18.7 17.2 13.8 Densitv (- a 4° drop in the next 50 meters. The x'olumes of the surface and 100-meter tows were one-half larger than that of the 50-meter tow. .Again just half of the species (50 per cent) were each confined to a single level; 11 were present at all three levels. The vertical distribution was 31 species at the surface, 33 at 50 meters, and 47 at 100 meters. This is the first appearance of Pontella princeps, which was found at a few of these eastern Pacific stations and nowhere else. Corycaeus, Farranula, Oithona, and Oncaea were each repre- sented by many species, well scattered through all three tows. Candacia, Eucalanus, Haloptilus, Heterorhabdus, Lucicutia. and Rhincalanus were each confined to the deeper tows and did not appear at the surface. The 100-meter tow showed an exceptionally high percentage of Oncaea and contained both species of Acartia. 56 COPEPODS OF LAST CRUISE OF CARNEGIE Station 46 November 21, 1928; 9° 06' S, 108° 20' W; bottom depth, 2905 m; 57 species Depth of tow, m Temperature, °C Salinity, Oy'oo X'olume of tow, cm' 50 100 Depth of tow, m 2,1.3 23.2 22.5 Density (tr,p) 35.3 35.3 35.4 Hydrogen-ion cone. (pH) 128 64 32 Length of tow, miles 24.1 8.16 1.8 50 24.3 8.16 1.8 100 24.8 8.17 1.8 Acartia danae f negligens Acrocalanus gracilis 4 monachus Calanus minor Calocalanus pavo Candacia simplex Centropages calaniniis violaceus Clausocalanus furcatus Clytemnestra scutcllata Corycaeus andrewsi catus crassiusculus flaccus limbatus oyalis pacificus pumilus r robustus 2 speciosus typicus 1 Eiicalanus monachus Euterpina aculifrons 1 Farranula carinata a curta gibbula a gracilis c rostrata a c r 3 2 f 3 19 2 Haloptilus longicornis. . . Labidocera detruncata . . Lucicutia clausii flavicornis Macrosetella gracilis. . . . oculata Mecynocera clausi Microcalanus pygmaeus. Microsetella rosea Neocalanus gracilis Oithona attenuata plumifera similis spinirostris Oncaea conifera media minuta notopa similis tenella venusta Paracalanus parvus Pontella atlantica princeps Pseudocalanus gracilis. . minutus Rhincalanus cornutus. . . Undinula darwinii r c 29 There was less than 1° of difterence in temperature through- out the upper 100 meters, and practically no difference in salinity and hydrogen-ion concentration. The three tows were also of exactly the same length, yet the surface tow had twice the volume of the 50-meter tow and four times the volume of the 100-meter tow. Twenty-two species (40 per cent) each were confined to a single level and 11 were present at all three levels. In \ertical distribution, 20 species were found at the surface, 39 at the 50-meter level, and 44 at the 100-meter level. Corycaeus and Oncaea continued to be represented by many species, but Candacia and Eiicalanus were each reduced to a single species. Curiously enough, whereas the Corycaeus species were as well distributed through all three tows as before, not a specimen of any Oncaea species appeared at the surface, and only 1 of the 4 species of Oithona. The surface tow contains the only record for Pseudocalanus gracilis. LISTS OF SPECIES BY STATIONS 57 Station 47 November 23, 1928; 14° 07' S, 111° 50' VV; bottom depth, 3080 m; 53 species Depth of tow, m Temperature, "C Salinity, o/oo \'olume of tow, cm^ 50 100 Depth of tow, m 50 100 23.8 23.8 22.7 Density (crip) 24.4 24.7 25.3 35.9 35.9 36.1 Hydrogen-ion cone. (pH) 8.23 8.23 8.23 144 38 32 Length of tow, miles 1.1 1.1 1.1 Acartia danae . . c negligens r 3 Acrocalanus gracilis r Calocalanus pavo r f plumulosus . . 1 styliremis . . r Candacia simplex 3 r Centropages calaninus . . 1 Clausocalanus arcuicornis f furcatus a Clytemnestra scutellata 2 Corycaeus agilis flaccus . . 1 lautus 1 limbatus f f longistylis 2 1 pumilus speciosus . . f typicus . . f Eucalanus monachus . . 3 Euchirella brevis . . 1 Farranula carinata c a concinna 2 c curta . . f gibbula c gracilis . . f rostrata a a Haloptilus longicornis. . . Labidocera detruncata. . Mecynocera clausi Microcalanus pygmaeus. Microsetella norvegica. . rosea Neocalanus gracilis Oithona attenuata similis spinirostris Oncaea curta minuta notopa similis tenella Paracalanus parvus pygmaeus Pontella danae securifer Pseudocalanus minutus. Rhincalanus cornutus. . . Sapphirina auronitens. . nigromaculata Temora discaudata stylifera Undinula darwinii Only 1° of difference in temperature in the upper 100 meters, and almost no difference in salinity and hydrogen- ion concentration. The three tows were of equal length, and the volume of the surface tow was from four to four and a half times that of the others. Thirty-two spscies (60 per cent) were each confined to a single level and 7 were present at all three levels. The vertical distribution was 25 species at the surface, 34 at the 50-meter level, and 23 at the 100-meter level. Candacia and Eucalanus were each again reduced to a single species. Corycaeus was represented by 8 species and Farranula by 6, all well distributed in the three tows. But not a specimen of any of the 5 species of Oncaea appeared at the surface, although one of them, 0. minuta, was abundant in the 50- meter tow. 58 COPEPODS OF LAST CRUISE OF CARNEGIE Station 48 November 25, 1928; 19° 06' S, 114° 07' W; bottom depth, 2874 m; 54 species Depth of tow, m Temperature, °C SaUnity, o/oo Volume of tow, cm' 50 100 23.6 23.6 22.7 36.4 36.4 36.2 32 32 32 epth of tow, m 50 100 Density (16'" a.m.; surface only. Twenty-one of the 40 species here taken at the surface were confined to the 50-meter and 100-meter levels at stations 49 and 50. Several others that were taken in the surface tow at one or the other of those two regular stations are here found in greater numbers. We are thus furnished with good evidence of the nocturnal migration to the surface of considerably more than half of the species here listed. LISTS OF SPECIES BY STATIONS Depth of tow, m Temperature, °C Salinity, o/oo Volume of tow, cm^ Station 50 November 29, 1928; 26° 27' S, 115° 21' W; bottom depth, 2837 m; 66 species 50 100 Depth of tow, m 23.2 22.0 20.5 Density (--five species, or about two-thirds, were each confined to a single tow, and only 5 were present in all three tows. There was less than 3° difference in the temperature at the three depths, and prac- tically no difTerence in the salinity and h>drogen-ion concen- tration. The smaller species of Corycaeus, Farranula, and Oncaea are much in evidence at this station. But again, whereas Corycaeus and Farranula species appear in all three tows, the Oncaea species are entirely absent from the surface. The 100-meter tow contains one of two records of Valdiviella minor outside the 1000-meter tow at station 64 (6). The two Haloptilus species are in the 100-meter tow, but Heterorhabdus appears in the 50-meter tow. 62 COPEPODS OF LAST CRUISE OF CARNEGIE Between stations 50 and 51 (a) November 30, 1928; 28° 38' S, 114° 59' W; 42 species Tow V'olume of tow. cm^ 1 36 2 32 Tow Length of tow, miles 1 2.3 2 2.0 Acrocalanus gracilis Aetideus armatus Calocalanus plumulosus. . . Candacia aethiopica bispinosa simplex truncata Centropages calaninus. . . . Clausocalanus arcuicornis. furcatus Corycaeus crassiusculus. . . flaccus lautus pumilus Euchaeta marina Farranula carinata concinna gibbula gracilis rostrata Lucicutia clausii 2 1 3 1 1 1 a c r f 3 r r 2 1 4 r f c r r c c f r a a f Macrosetella oculata Metridia brevicauda Microcalanus pusillus Neocalanus gracilis robustior Oithona similis Oncaea curta media minuta similis subtilis tenella Paracalanus parvus Pleuromamma abdominalis. Pontella tenuiremis Pontellina plumata Pseudocalanus minutus. . . . Sapphirina nigromaculata . . Spinocalanus abyssalis Undinula caroli darwinii c 1 f a 1 c f c a Time of first tow, 7''35" to 9'' p.m.; of second tow, 9''20"' to 10''30™ P.M. Surface only. These two tows, in conjunction with the one which follows, furnish exceptional evidence of nocturnal diversity of distribution among the surface cope- pods. These two were taken consecutively with the same net at the same localitj*. As the ship was becalmed and the interval between tows was only 20 minutes, the areas covered were so close together as to warrant no change in the record of latitude and longitude. The first was an 85-minute tow, the second a 70-minute tow, with a difference in volume cor- responding to that in length. The two together yielded 42 species of copepods; 13 of these appeared in the first tow but not in the second, and 10 were found in the second tow- but not in the first. This made a total of 23 species, or 55 per cent, which were confined to one of the localities. Furthermore, of the 19 species found in both tows, only 6 were credited with the same relative abundance, the other 13 showing notable differences. Hence 86 per cent of the entire catch shows more or less diversity of distribution, a remarkable result when the proximit)' of the two tows is taken into consideration. Between stations SO and 51 (b) November 30, 1928; 28° 45' S, 114° 55' W; 44 species Acartia negligens 2 Acrocalanus gracilis f Candacia bispinosa 2 simplex r Centropages calaninus a Clausocalanus arcuicornis c furcatus r Corycaeus catus 1 crassiusculus r lautus 2 limbatus 3 typicus r Euchaeta marina 2 Farranula carinata c concinna c Farranula gibbula a gracilis c rostrata c Heterorhabdus papilliger 1 Labidocera detruncata f Lubbockia squillimana 1 Lucicutia clausii a flavicornis f Metridia longa 1 Microcalanus pygmaeus 1 Microsetella rosea 1 Neocalanus robustior a Oithona similis f Oncaea conifera 1 curta f Oncaea media a minuta c similis c venusta 2 Paracalanus parvus f Pleuromamma abdominalis 4 Pontella tenuiremis r Pontellina plumata 2 Pseudocalanus minutus c Sapphirina auronitens r Spinocalanus abyssalis c caudatus 1 Undinula darwinii a \'aldiviella minor 4 LISTS OF SPECIES BY STATIONS 63 Volume of tow, 36 cm'; length, 2.9 miles; time, ll''!?"' p.m. to 12''30"' A.M. This third surface tow was taken with the same net later during the same night, but in the interval the ship had moved several miles from its former position. This tow contains 16 species that do not appear in the two former tows and it fails to show 14 species that were found there. In the three tows, therefore, 40 of the 58 species (70 per cent) appear in a single tow only, and many of the remaining 30 per cent show marked differences in their relative abundance. Val- diviella minor here appears at the surface in the night, whereas the other two records are in the 100-meter tow at station 50 and the 1000-meter tow at station 64. This species, then, is another that migrates to the surface in the night, but stays below 100 meters most of the time during the day. Station 51 December 1, 1928; 29° 06' S, 114° 48' W; bottom depth, 2898 m; 50 species Depth of tow, m Temperature, °C Salinity, 0/00 X'olume of tow, cm' 50 100 Depth of tow, m 50 100 22.7 20.5 19.9 Density (fftp) 24.4 25.3 25.7 35.6 35.5 35.6 Hydrogen-ion cone. (pH) 8.22 8.22 8.22 37 36 35 Length of tow, miles 1.6 1.2 1.2 Acrocalanus gracilis c Calocalanus pavo Candacia bispinosa simplex Centropages calaninus f Clausocalanus arcuicornis f Clytemnestra scutellata Copilia denticulata quadrata Corycaeus agilis catus a crassiusculus lautus r limbatus typicus Farranula carinata c concinna f carta 2 gibbula a gracilis c rostrata Haloptilus acutifrons longicornis Heterorhabdus spinifrons Labidocera detruncata f Lucicutia clausii Macrosetella gracilis. . . . Mecynocera clausi Metridia brevicauda. . . . Microcalanus pygmaeus. Microsetella rosea Neocalanus gracilis robustior tenuicornis Oithona attenuata plumifera similis spinirostris Oithonina nana Oncaea media minuta similis Paracalanus parvus Pleuromamma gracilis. . Pontella tenuiremis Pontellina plumata Pseudocalanus minutus. Sapphirina auronitens. . Undinula caroli darwinii The temperature differed less than 3° in the 100 meters, and the salinity and hydrogen-ion concentration showed no variation. Fifteen species were found at the surface, only 5 in the 50-meter tow, and 42 in the 100-meter tow. Thirty-nine species (78 per cent) were each confined to a single tow and only 1, Pseudocalanus minutus, was present in all three tows- In the small number of copepods, only 8 in all, that are recorded for the 50-meter net, this list differs radically from all the others. Something must have happened to this tow which does not appear anywhere in the records. 64 COPEPODS OF LAST CRUISE OF CARNEGIE Station 52 December 3, 1928; 31° 28' S, 112° 51' W; bottom depth, 2851 m; 52 species Depth of tow, m Temperature, °C SaHnity, o/oo Volume of tow, cm' 50 100 Depth of tow, m 50 100 22.4 20.1 18.2 Density (utp) 24.4 25.0 25.8 35.3 35.6 36.2 Hydrogen-ion cone. (pH) 8.21 8.20 8.17 36 37 48 Length of tow, miles i.y 1.0 1.0 Acartia negligens Acrocalanus gracilis longicornis Aetideus armatus Calocalanus pavo plumulosus Candacia simplex Clausocalanus arcuicornis. Copilia quadrata Corycaeus agilis catus crassiusculus flaccus lautus typicus Euaetideus giesbrechti. . . . Euchaeta marina Euchirella brevis Farranula carinata concinna gibbula rostrata Haloptilus longicornis Heterorhabdus spinifrons. Lubbockia squillimana. . . . Lucicutia clausii Macrosetella gracilis oculata Mecynocera clausi Microcalanus pygmaeus. . . . Microsetella rosea Neocalanus gracilis robustior Oithona attenuata similis spinirostris Oncaea curta minuta notopa similis tenella venusta Paracalanus parvus Pleuromamma abdominalis. gracilis Pontella tenuiremis Pontellina plumata Pseudocalanus minutus. . . . Sapphirina auronitens opalina Spinocalanus abyssalis Undinula darwinii The temperature varied a little more than 4° at the three depths. The salinity rose a little and the hydrogen-ion con- centration fell as the depth increased. Fourteen species were at the surface, 19 in the 50-meter tow, and 44 in the 100- meter net. Thirty-three species (63 per cent) were each con- fined to a single depth and only 5 appeared at all three depths. Of the 14 appearing at two depths, 8 showed a decided prefer- ence for one depth over the other. The 6 species of Oncaea with one exception were confined to the 100-meter tow, and the 6 species of Corycaeus and the 4 species of Farranula were well distributed in all three tows. Although all 3 species of Oithona were found to be abundant in the 50-meter tow, it is to be noted that not a single specimen was found at the surface. LISTS OF SPECIES BY STATIONS 65 Station 53 December 5, 1928; 29° 06' S, 108° 44' \V; bottom depth, 2871 m; 66 species Depth of tow, m Temperature, °C Sahnity, 0/00 \'olume of tow, cm' 50 100 Depth of tow, m 50 100 22.5 21.2 19.9 Density (' specimen of Corycaeus catus taken at the surface. One specimen of the new Onchocalanus was captured in the surface tow. Candacia, Euchaeta, Haloptilus, Hetero- rhabdus, Lucicutia, and Undeuchaeta were all confined to the 100-meter tow, except Lucicutia curta. 68 COPEPODS OF LAST CRUISE OF CARNEGIE Station 55 December 16, 1928; 32° 03' S, 110° 55' W; bottom depth, 2725 m; 82 species Depth of tow, m Temperature, °C Salinity, o/oo X'olume of tow, cm' 50 100 Depth of tow, m 50 100 20.3 18.7 16,7 Density (- num- bers at station 56, not one of the same 5 species was found here in the surface tow. This would seem to indicate that Farranula may become somewhat phototropic, although usually much less so than Corycaeus and Oncaea. AH the specimens in the surface tow were very badh' mutilated, and if this means an accident, it will go far toward explaining the exceptionally small number of species in that tow. 72 COPEPODS OF LAST CRUISE OF CARNEGIE Station 58 December 22, 1928; 36° 51' S, 104° 05' W; bottom depth, 3810 m; 36 species Depth of tow, m Temperature, °C Salinity, o 'oo X'olume of tow, cm' 50 100 Depth of tow, m 50 100 16.9 14.8 12.3 Density (o-tp) 24.7 25.4 26.3 33.9 3-t 34.0 Hvdrogen-ion cone. (pH) 8.12 8.12 8.09 448 36 96 Length of tow, miles 1.3 1.3 1.3 Acrocalanus gibber gracilis Canthocalanus pauper. . , . Clausocalanus arcuicornis. furcatus Corycaeus crassiusculus. . . pumilus typicus Eucalanus elongatus Euchaeta acuta Euchirella rostrata Farranula curta rostrata Lucicutia clausii Mecynocera clausi Megacalanus longicornis. . Microcalanus pusillus pygmaeus Neocalanus gracilis robustior tenuicornis Oithona brevicornis. . . . similis spinirostris Oithonina nana Oncaea conifera media minuta similis venusta Paracalanus parvus Pleuromamma gracilis. . Pseudocalanus minutus. Sapphirina angusta Scolecithrix danae Undinula darwinii From a low surface temperature there was a drop of 4?5 in the upper 100 meters, and the salinity and hydrogen-ion concentration remained moderately high and constant. Only 4 species appeared at the surface, 24 in the 50-meter tow, and 25 in the 100-meter tow. Twenty-one species (60 per cent) were each confined to a single tow and only 2 were found in all three tows. This station is notable for the small number of species found at the surface. This may be due to the fact that the great bulk of this tow was made up of cteno- phores. These feed on copepods, among other creatures, and when they swarm in large numbers, as they were doing here, they would naturally reduce the number of the copepods. This would also help explain the great drop in number of species from 108 at station 56 and 80 at station 57 to 36 here. Station 59 December 24, 1928; 39° 51' S, 101° 04' \V; bottom depth, 4116 m; 24 species Depth of tow, m Temperature, °C Salinity, o/oo X'olume of tow, cm' 50 100 Depth of tow, m 50 100 16.3 13.9 11.4 Density ( SO" to 5'' 50"- p.m.; 40° 26' S, 97° 12' W B. December 26, 1928, 7>' SO"- to lO"- 20°' p.m.; 40° 22' S, 97° 02' W C. December 26, 1928, 10'' 25"' p.m. to l"" a.m.; 40° 22' S, 96° 59' W 16 species Location of tow \ olume of tow, cm' A 64 B 36 Location of tow- Length of tow, miles A 3.0 C 1.6 Acrocalanus gracilis Calanus tonsus Clausocalanus arcuicornis. furcatus Microsetella rosea Neocalanus gracilis Oithona brevicornis similis Oncaea curvata similis Paracalanus parvus Pleuromamma gracilis . . Pseudocalanus minutus. Scolecithri.x danae Undeuchacta major. . . . Undinula darwinii These three surface tows were taken the same night but a few miles apart. The first tow, from S"* to 6'' in the late after- noon, yielded 7 species; the second tow, from S"" to 10'' in the evening, yielded only 2 species; and the third tow, over mid- night, yielded IS species. It is also worthy of note that the third tow, although shorter than the second, yielded a volume eight times as large, and this volume was four and a half times that of the first tow, although the latter was twice as long. That the midnight tow should contain twice as many species as either of the others is, however, exactly what would be expected as a result of nocturnal migration. The species found in it that were not present in the other tows are the ones that require a longer time to reach the surface. This may be due to slower progress or to a longer distance traversed, Undeuchacta probably coming under the latter al- ternative, and Oncaea perhaps representing the former. Clauso- calanus and Oithona comprised 99 per cent of the first tow, the second tow was e\-enly di\-ided between Oithona and Cala- nus, and no single species of the third tow stood out with any prominence. Nine of the species (56 per cent) were each con- fined to one of the tows, and only a single species was present in all three tows. These three tows thus present considerable diversity in the surface distribution of the copepods, appar- ently due to the time of day at which the hauls were made. 74 COPEPODS OF LAST CRUISE OF CARNEGIE Station 61 December 28, 1928; 38° 29' S, 94° 14' \V; bottom depth, 3299 m; 26 species Depth of tow, 111 Temperature, °C Salinity, o/oo \olume of tow, cm' 50 100 Depth of tow. 111 50 100 16. q U.O 10.7 Density ffftp) 24.8 25.6 26.5 .u.o 33 . 9 34.0 Hvdrogen-ion cone. (pH) 8.05 8.05 8.03 320 36 36 Length of tow, miles 1.5 1.1 1.1 Calocalanus pavo plumulosus stylireniis Clausocalanus arcuicornis. Eucalanus mucronatus. . . . Euchirella brevis Farranula curta gibbula rostrata Heterorhabdus papilliger. . Heterostylites longicornis. Mecynocera clausi Microcalanus pygmaeus. . . Neocalanus gracilis. . . . tenuicornis Oithona brevicornis. . . similis spinirostris Oithonina nana Oncaea curvata similis Paracalanus parvus. . . . Pseudocalanus minutus Scolecithrix danae Undinula darwinii X'ettoria granulosa . . . . The temperature was still low at the surface and dropped 6° in 100 meters; the salinitj- and hydrogen-ion concentration were moderate and constant. Four species were found at the surface, 13 in the 50-meter tow, and 19 in the 100-meter tow . Seventeen species (65 per cent) were each confined to a single tow and only 1 was present in all three tows. The length of the surface tow was four-tenths greater than that of the other two tows, but its \olume was nine times as large. Since it contained but 4 copepod species, 1 of which was represented b>- a single specimen, its bulk was manifestly due to plankton other than the copepods. The 50-meter tow contained 13 species, but more than 90 per cent of its copepods were Mecynocera clausi. .Similarly, development stages of the 3 species of Oithona made up a large part of the 100-meter tow. Between stations 61 and 62 A. December 28, 1928, W^ 50" p.m. to 2'' a.m.; 37° 35' S, 93° 35' \V B. December 29. 1928, 2^ to 2'' 45- a.m. ; 37° 34' S. 93° 35' W 36 species Location of tow \olume of tow, cm' .A 36 B 32 Location of tow Length of tow, miles .A 0.4 B 7 1 Acartia danae Acrocalanus gracilis Calocalanus plumulosus. . . Candacia simplex Clausocalanus arcuicornis. furcatus Corycaeus agilis catus crassiusculus pumilus Farranula rostrata Microcalanus pusillus pygmaeus Microsetella rosea Neocalanus gracilis robustior Oithona similis Oncaea media f 1 c a c a 1 f 2 c 2 f a 1 f r 3 1 c f r 2 1 f f f Oncaea mediterranea f niinuta c notopa r similis c venusta a Paracalanus parvus f pygmaeus 1 Pleuromamma gracilis c Pontella atlantica 1 Pseudocalanus minutus c Sapphirina angusta 1 auronitens Scolecithricella bradyi 3 niarginata 1 Scolecithrix danae f Spinocalanus abyssalis c Undinula darwinii f Vcttoria granulosa 3 LISTS OF SPECIES BY STATIONS 75 These two surface tows were taken at about the same time, only a mile apart. One yielded 28 species and the other 30. Fourteen species (40 per cent) were each confined to one of the tows, and 22 species (60 per cent) were present in both tows. This is a much more even distribution than that of the tows taken between stations 60 and 61. It is worthy of note that although one tow covered a distance five and a half times as great as the other, the difference in volume is in favor of the shorter tow. Tow A contains one of three records o{ Pontella atlantica in the eastern Pacific. In both tows (taken near midnight), S of the 6 species of Oncaea appear in \ aried abundance; the si.xth species was absent from tow B. St.ation 62 December 30, 1928; 34° 35' S, 91° 52' W; bottom depth, 3610 m; 36 species Depth of tow, m Temperature, °C Salinity, o/oo X'ohuiie of tow, cm' 50 100 Depth of tow, m .SO 100 19.2 16.2 13.1 Density (ctip) 24.4 2.S.3 26.2 34.2 34.2 34.1 Hvdrogen-ion cone. (pH) 8.12 8.10 8.06 36 36 36 Length of tow, miles 0.1 0.1 0.1 -\c- solitary specimens. Hence, although this deep tow added materially to the num- ber of species obtained, it was very meager in individual specimens. Pleitromamma gracilis is recorded as abundant and 5 species are recorded as common; these are all, except Oncaea conifera, abundant in the upper 100 meters, and of course may ha\e been obtained there as the net was drawn to the surface. Since the net was drawn horizontally at a depth of 1000 meters for a reasonable distance, the paucity of speci- mens in the case of the 9 species mentioned above would seem to suggest that none of them congregates at a depth of 1000 meters. On the contrary, their downward migration during the daytime probably stops at a level between 100 and 1000 meters. That would explain why they were not taken in the regular 100-meter tow, and wh>- so few of them were captured as the net passed \erticalK' ii|)ward through tlie le\el where they had stopped. LISTS OF SPECIES BY STATIONS 83 Between stations 64 and 65 (o) A. January 3. 1929, 10'> to W' p.m.; 31° 52' S, 87° 51' W B. January 4, 1929, 0" to 2" a.m.; 31° 52' S, 87° 46' W 40 species Location of tow Volume of tow, cm' A ,S2 B 32 Location of tow Length of tow, miles A 0,6 B 2.4 Acartia danac negligens Acrocalanus gibber gracilis Candacia norvegica simplex Clausocalanus arciiicornis. furcatus Clytemnestra rostrata . . . . Corycaeus agilis crassiusculus speciosus Farranula carinata curta gracilis rostrata Macrosetella gracilis Megacalanus longicornis. . Microsetella norvegica. . . . Neocalanus gracilis Neocalanus robnstior. . . tenuicornis Oithona similis Oncaea curta media mediterranea minuta notopa similis tenella venusta Paracalanus parvus pygmaeus Pleuromamma gracilis. . Pseudocalanus minutus. Sapphirina opalina Scolecithri.x danae Spinocalanus abyssalis. . Undinula caroli darwinii These two surface tows were taken on the same night about 5 miles apart. Twent>-nine species were taken in tow A, just before midnight, and 31 in tow B, just after midnight. Twenty of the species, or e.xactly half, were each confined to one of the tows, and the other 20 were present in both tows. The volume of the two tows was exactly the same although tow B was four times the length of A. The copepod species must ha\e been considerabh' more numerous just before mid- night than after, as would be expected. But the greater length of the earh morning tow more than offset the superior abun- dance in the one before midnight and produced 2 more species. Oncaea surpassed Corycaeus and Farranula combined, both in number of species and in abundance. Megacalanus appears in both tows and e\idently does not alwa\s begin its downward migration from the surface promptly. 84 COPEPODS OF LAST CRUISE OF CARNEGIE Between stations 64 and 65 (i) A. January 4, 1920, 2>' to 4'' a.m.; 31° 52' S, 87° 42' \V B. January 4, 1929, 6'> 45"' to 10'' p.m.; 31° 31' S, 86° 57' W 44 species Location of tow X'ulunic of tow, cm^ A 32 B 36 Location of tow Length of tow, miles A 1.6 B 2.0 Acartia danae c negligens c Acrocalanus gracilis f Calocalanus pluniulosus Candacia norvegica 4 Centropages calaninus 2 Clausocalanus arcuicornis a f urcatus c Clytemnestra rostrata 1 Corycaeus agilis 3 catus 1 clausi 2 crassiusculus f flaccus 3 pinnilus r speciosus f typicus f Farranula carinata c curta a gibbula r rostrata a Mecynocera clausi 1 Megacalanus longicornis 3 Neocalanus gracilis f robustior 2 Oithona similis 1 Oncaea curta f media c mediterranea c minuta a notopa a similis r tenella a venusta a Paracalanus parvus c pygmaeus f Pleuromamma gracilis f Pseudocalanus minutus c Sapphirina auronitens 1 pyrosomatis salpae 1 Scolecithricella bradyi 2 Undeuchaeta plumosa 4 Undinula darwinii a Two surface tows taken the same day at a considerable distance apart, tow A in the early morning and tow B in the late evening. Of the total of 44 species, tow A contained all but 2, and tow B only 17. Twenty-nine species (66 per cent) were confined to one tow and IS were found in both tows. The great difference in the number of species in the two tows is good evidence that the downward migration begins at or shortly after midnight. Megacalanus was confined to the tow shortly after midnight, and had not reached the surface at 10 P.M. LISTS OF SPECIES BY STATIONS 85 Station 65 January 5, 1929; 31° 07' S, 86° 39' W; bottom depth, 3626 m; 42 species Depth of tow, m Temperature, °C Sahnity, 0/00 \'ohiine of tow, cm^ SO 100 Depth of tow, m 50 100 20.2 16.5 14.8 Density (ertp) 24..^ 25.4 25.9 ,U.5 34.4 .Ul H^■drogen-ion cone. (pH 1 8.10 8.10 8.10 96 il 48 Length of tow, miles o.y 0.5 0.5 Acartia danae negligcns Acrocalanus gibber gracilis Calanus minor Calocalanus plumulosus. . . Candacia simple.'c Clausocalanus arcuicornis. Corycaeus agihs dubius flaccus pacificus pumilus typicus Farranula carinata gibbula rostrata Hetcrorhabdus papilhger, . Luciciitia clausii Havicornis Mecynocera clausi Metridia lucens Microcalanus pygmaeus. . . . Microsetella rosea Neocalanus gracilis robustior tenuicornis Oithona attenuata fallax setiger similis spinirostris Oncaea minuta venusta Paracalanus parvus pygmaeus Pleuromamma abdominalis. gracilis Pseudocalanus minutus. . . . Sapphirina salpae Scolecithrix danae Undinula darwinii The temperature was moderate at the surface and dropped 5?5 in 100 meters; the salinity and hj'drogen-ion concentra- tion were fairly high and constant. Thirteen species were taken at the surface, 21 in the SO-meter tow, and 31 in the 100-nieter tow. Twenty-seven species (64 per cent) were each confined to a single tow and 8 were present in ail three tows. Corycaeus, Farraniila, and Oithona were well represented in species, and although there were only 2 species of Oncaea they were both abundant in the two deeper tows. The 4 specimens of Metridia lucens in the 50-meter tow constituted the largest number of the species taken at any station in the eastern Pacific. Mecynocera, which was represented by a single specimen in the four preceding surface tows, is here common in the 50-meter tow and abundant in the 100-meter tow. Ileterorhabdus, the three Neocalanus species, and Pleuro- mamma appear only in the 100-meter tow. The surface tow was virtually an exclusive colony of Clausocalanus, the other species combined failing below 10 per cent. 86 COPEPODS OF LAST CRUISE OF CARNEGIE Station 66 January 7, 1929; 27° 04' S, 84° 01' W; bottom depth, 3812 ni; 45 species Depth of tow, m Temperature, °C Salinity, o/oo V'olume of tow, cm' 50 100 Depth of tow, m 50 100 19.4 17.8 17.8 Density (atp) 24.6 25.4 25.7 34.6 34.8 34.9 Hydrogen-ion cone. (pH) 8.10 8.10 8.12 64 64 Length of tow, miles 1.7 .... 1.7 Acartia danae negligens Acrocalanus gibber gracilis longicornis Calanus propinquus Calocalanus pavo Candacia bipinnata bispinosa longimana simplex Clausocalanus arcuicorni.s. Corycaeus flaccus lautus longistylis pacificus pumilus typicus Euaetidcus giesbrcchti. . . . Euchaeta acuta Farranula carinata rostrata ('•aidius tcnuispinus Heterorhabdus papilliger. Lubbockia squillimana. . . Lucicutia flavicornis Mecynocera clausi Microsetella rosea Neocalanus gracilis robustior tenuicornis Oithona attenuata fallax siniilis spinirostris Oncaea minuta venusta Paracalanus parvus Pleuromamma gracilis. . . Pseudocalanus minutus. . -Sapphirina auronitens. . . . mctallina .Scolecithricella bradyi . . . .Scolecithrix danac Undinula darwinii 3 3 c c f c f c f f c f a a f ^ f 2 4 f c The temperature was moderate and dropped less than 2° in 100 meters; the salinity and hydrogen-ion concentration were again fairlj' high and constant. Nineteen species were found at the surface and 41 in the 100-meter tow, yet the two tows had exactly the same length and volume. The 100- meter tow at this station, the 50-meter tows at stations 41 and 44, and the 1000-meter tow at station 64 were the only records for Gaidius tenuispiniis in the eastern Pacific. It evidently seeks a level below 100 meters during the da\time and is not abundant anywhere. The 4 Candacia species, 2 of the Neocalanus species, 3 of the Oithona species, and the single species of Pleuromamma were confined to the 100- meter tow, and none of them were abundant. Thirty species (66 per cent) appeared in one tow and not in the other, and 15 were common to both tows. Apparently the catch of the SO-meter tow was lost; no specimens were axailablc. LISTS OF SPECIES BY STATIONS 87 Station 67 January 8, 1929; 24° 57' S, 82° 15' W; bottom depth, 1089 111; 45 species Depth of tow, 111 Temperature, °C Salinity, 0/00 Volume of tow, cm'' 50 100 Depth of tow, m 50 ino 19.2 17.3 16.2 Density ('-fi\e species (55 per cent) were each confined to a single tow and 6 were found in all three tows. Corycaeus and Oilhona presented many species, but comparatively few specimens, and this paucity in numbers was shared by nearly all the other genera, since only two of them were recorded as abundant. As at the two preceding stations, Microsetella w^as found onl\- in the 100-meter tow, although it is usually a surface form. 88 COPEPODS OF LAST CRUISE OF CARNEGIE Station 68 January 10, 1929; 21° 28' S, 80° 26' W; bottom depth, 4156 m; 32 species Depth of tow, m Temperature, "C Salinity, o/oo Volume of tow, cm' 50 100 Depth of tow, m 50 100 19.1 18.2 16.5 Density (ctip) 25.0 25.4 25.9 35.1 35.0 34.8 Hydrogen-ion cone. (pH) 8 14 8.14 8.13 32 36 48 Length of tow, miles 0.9 1.0 1.0 Acartia danae negligens Acrocalanus gracilis Calanus propinquus Calocalanus pavo Canthocalanus pauper. . . . Clausocalanus arcuicornis. furcatus Clytemnestra scutellata. . . Eucalanus attenuatus elongatus Heterorhabdus papilliger. . Lucicutia clausii Mecynocera clausi Megacalanus longicornis. . princeps Miracia efferata Ncocalanus gracilis tenuicornis Oithona fallax linearis setiger similis spinirostris Oncaea minuta notopa venusta Paracalanus parvus Pseudocalanus minutus. . . Sapphirina nigromaculata. Scolecithricclla porrecta. . . Undinula darwinii The temperature was rather low at the surface and dropped less than 3° in the 100 meters; the salinity and hydrogen-ion concentration were high and changed very little. Twelve species were captured at the surface, 1 1 in the 50-meter tow, and 23 in the 100-meter tow. Twenty-two species (70 per cent) were each restricted to a single tow and only 4 were found in all three tows. The single record for Oithona linearis and one of \ery few for Scolecithricella porrecta were found in the 100-meter tow. This is one of the rare stations where none of the three tows contained a single specimen of any Corycaeus species. Again the Oncaea species were present at the surface but were not so abundant as in the deeper tows. Four of the 5 Oithona species were confined to the 100-meter tow. LISTS OF SPECIES BY STATIONS 89 I Station 69 January 12, 1929; 16° 49' S, 78° 39' W; bottom depth, 3657 m; 54 species Depth of tow, m Temperature, °C Salinity, 0/00 \'olume of tow, cm' 50 100 Depth of tow, m 21.1 17.3 14.5 Density (crtp) 35.2 35.1 34.8 Hydrogen-ion cone. (pH) 48 32 64 Length of tow, miles 24.6 8.12 1.0 50 25.7 7.99 0.9 100 26.4 7.86 0.9 Acartia danae negligens Acrocalanus gracilis nionachus Aetideus armatus Calanus propinquus Calocalanus plumulosus. . . Candacia simple.\ Canthocalanus pauper. . . . Clausocalanus arcuicornis. Clytemnestra rostrata . . . . Corycaeus crassiusculus. . . pumilus speciosus typicus Eucalanus attenuatus crassus elongatus Euchaeta marina Euchirella brevis pulchra Farranula carinata gibbula rostrata Haloptilus longicornis Hetcrorhabdus papilliger. . spinifrons Lucicutia clausii flavicornis Macrosetella gracilis Mecynocera clausi Metridia brevicauda lucens Microsetella norvegica rosea Neocalanus gracilis Oithona attenuata plumifera 4 similis a spinirostris Oithonina nana Oncaea media f minuta c venusta c Paracalanus parvus c pygmaeus Phaenna spinifera 1 Pleuromamma gracilis Pseudocalanus minutus f Sapphirina angusta auronitens 1 nigromaculata Scolccithricella minor Undinula darwinii f The surface temperature was higher but it fell nearly 7° in the 100 meters; the salinity and hydrogen-ion concentra- tion were high at the surface but diminished a little in the two lower depths. Eighteen species were present at the sur- face, 30 in the 50-meter tow, and 36 in the 100-nieter tow. Thirty-four species (63 per cent) were each confined to a single tow and 10 were present in all three tows. Five species alone were recorded as abundant, and nearly half of the records were numerals, 15 of them each a single specimen. Aetideus, Haloptilus, and Metridia were found only in the 100- meter tow, and the same was true of all but one of the Cory- caeus species. On the other hand, each of the Oncaea species was present at the surface, but 2 of them were more abundant in the deeper tows. 90 COPEPODS OF LAST CRUISE OF CARNEGIE Station 70 January 13, 1929; 13° 53' 8, 77° 54' W; bottom depth, 4742 m; 42 species Depth of tow, m Temperature, °C SaHnity, o/oo Volume of tow, cm' 50 100 Depth of tow. m 50 100 21.2 15.4 12.5 Density (- species (61 per cent) were each restricted to a single tow and only 4 were present in all three tows. The length of the surface tow was a trifle less than half that of the other two tows, but its volume was six times as great. Thus some constituents of the plankton found conditions more suitable at the surface than at the other depths. The copepods showed a decided preference for the 50-meter depth. At the surface Labidocera constituted over 90 per cent of the copepods, and in the 50- meter tow Oncaea was especially abundant. Between stations 72 and 73 February 9, 1929; 10° 30' S, 84° 20' W; 16 species Acartia danae 2 Clausocalanus arcuicornis 1 Corycaeus crassiusculus f limbatus r Euchaeta marina a Farranula carinata 2 Farranula rostrata 1 Microsetella rosea 1 Oithona similis c spinirostris r Oncaea minuta f Oncaea venusta f Paracalanus parvus a Pseudocalanus minutus a Sapphirina auronitens 1 scarlata 1 Volume of tow, 48 cm'; length, 0.8 mile; surface only. This night-time tow must have been taken at an unfavorable hour (not recorded), since it yielded only 16 species. The single one that is at all noteworthy is the rare species Sapphirina scarlata, which is also found at the surface in the daytime and hence cannot be regarded as a migrant from below. This tow consisted almost entirely of Pseudocalanus, Euchaeta, and Paracalanns, abundant in the order named. LISTS OF SPECIES BY STATIONS 93 Station 73 February 10, 1929; 10° 46' S, 84° 57' VV; bottom depth, 4670 m; 38 species Depth of tow, m Temperature, °C Salinity, 0;'oo X'olume of tow, cm^ 50 ion Depth of tow, m 50 100 25.2 18.7 14.7 Den^itv (' found in the deejier tows in the da\'- time. Clausocalanus, Corycaeus, Farranula, and Pseudocalanus were each very abundant, whereas Rhincalanus and Sap- phirina were each represented by a single specimen. LISTS OF SPECIES BY STATIONS 97 Station 78 February 20, 1929; 13° 02' S, 108° 03' W; bottom depth, 3337 m; 41 species Depth of tow, m Temperature, °C Sahnity, o/oo \'o!ume of tow, cm^ 50 100 2.S . 8 21,') M> . ibA 80 32 Depth of tow. m I >ensity (uip) llydrogen-ion concentration (pH) Length of tow, miles 50 100 24.7 25 5 8.14 8.14 0.4 0.4 Acartia daiiae c f Acrocalanus gracilis . . f Amallothrix propinqua 1 Calanus minor f Calocalanus pave . . 1 plumulosus 2 Candacia simplex c Centropages calaninus . . 2 Clausocalanus arcuicornis . . f Corycaeus crassiusculus a c flaccus . . f minimus r speciosus . . 2 Euchirella messinensis 1 F-arranula carinata a gibbula 2 rostrata a Haloptilus longicornis 4 Heterorhabdus papilliger Lucicutia flavicornis 2 3 longicornis . . 2 Mecynocera clausi Microcalanus pygmaeus. Microsetella rosea Neocalanus gracilis robustior Oithona attenuata plumifera similis spinirostris Oncaea minuta venusta Paracalanus parvus pygmaeus Pontellina plumata Pseudocalanus minutus, Rhincalanus cornutus. . . Sapphirina auronitens. . . nigromaculata Tcmora discaudata longicornis The surface tow is lacking; the other two showed high temperature, salinity, and hydrogen-ion concentration, with little variation. Twenty-six species were taken in the 50- meter tow and 28 in the 100-meter tow. Twenty-eight species (70 per cent) were found in one tow and not in the other, and 13 were present in both tows. The 50-meter tow contains one of two Pacific records for Corycaeus minimus and 3 for Temora longicornis, and also has 2 other rare species, Amallo- thrix propinqua and Euchirella messinensis. Of the four genera rated as very abundant at the surface in the record of station 77, only two appear here as abundant in the 50-meter tow. Conversely, Rhincalanus, of which there was but a single specimen there at the surface, is here abundant in both the deeper tows. Farranula, Oncaea, and Mecynocera are also especially' abundant in the 50-meter tow, and Oithona in the 100-meter tow. 98 COPEPODS OF LAST CRUISE OF CARNEGIE Station 79 February 22, 1929; 12° 36' S, 112° 14' \V; bottom depth, 3090 m; 35 species Depth of tow, m Temperature, °C Salinity, o/oo \'oIume of tow, cm^ 50 100 Depth of tow. m 25.1 24.5 21.8 Density (', and h\drogen-ion concentration in both tows, with practical!)- no \-ariation. Thirty-one species were taken at the surface and 43 in the 50-meter tow. Thirty-four species (63 per cent) were present in one tow but wholly absent from the other, and 20 were taken in both tows. The 3 Eucalanus species, the 2 Euchirella species, Haloptilus. and Rhincalanus did not appear at the surface; the Candacia, Corycaeus, Farranula. Labidocera, Oncaea, and Undinula species were well di\ided between the two tows. The 50-meter tow was two and a half times the length of the surface tow and its volume was one and a half times as great. 100 COPEPODS OF LAST CRUISE OF CARNEGIE Station 81 February 26, 1929; 13° 03' S, 121° 12' W; bottom depth, 2953 m; 47 species Depth of tow. 111 Temperature, °C SaHnity, o/oo X'olume of tow, cm' 50 Depth of tow. 111 50 2f).S 26.4 Density (ctip) 23.5 23.8 J5.8 35.8 Hydrogen-ion concentration (pH) 8.19 8.19 48 96 Length of tow, miles 0.2 0.7 Acartia danae 2 Acrocalanus gracilis c Calanus minor Calocalanus pavo 1 Candacia bispinosa norvegica simplex a truncata Clausocalanus arcuicornis c Corycaeus crassiusculus a dubius r limbatus longistylis c speciosus c Eucalanus attenuatus crassus elongatus Euchaeta marina Euchirella curticauda Farranula carinata c gibbula f rostrata a Haloptilus longicornis Heterorhabdus papilliger Labidocera detruncata. . Lubbockia squillimana. . Mecynocera clausi Megacalanus princeps, . Microcalanus pusillus. . . pygmaeus Microsetella rosea Neocalanus robustior. . . Oithona attenuata pliimifera similis Oncaea curta minuta similis venusta Paracalanus parvus pygmaeus Pseudocalanus niinutus. Rhincalanus cornutus. . . Sapphirina auronitens. . Scolecithrix danae Undinula caroli darwinii The temperature, salinity, and hydrogen-ion concentration were high and did not change in the 50 meters. Twenty-three species appeared at the surface and 39 in the 50-meter tow. Thirty-two species (70 per cent) each were present in one tow and not in the other, and 15 were found in both tows. Again the Eucalanus species, EiicliireUa. Ilelerorhahdus, Luhhnckia, Megacalanus, and Rhincalanus were confined to the deeper tow, and Corycaeus, Farranula, Oithona, and Oncaea were well divided between the two tows. One species of Candacia was abundant in both tows; the other 3 species did not appear at all at the surface. Clausocalanus was found only at the surface. LISTS OF SPECIES BY STATIONS lOI Station 82 February 28, 1929; 14° 52' S, 126° 07' W; bottom depth, 3631 m; 52 species Depth of tow, m Temperature, °C Salinity, o/oo X'okime of tow, cm' 50 Depth of tow, m 50 27.2 27.2 Density (o-tp) 23.6 24.0 36.3 36.3 Hydrogen-ion concentration (pH) 8.21 8.21 32 64 Length of tow, miles 0.4 1.8 Acartia danae r f Acrocalanus gracilis f f monachus . . 5 Calanus minor . . c Calocalanus pavo . . f styliremis . . r Candacia bispinosa . . f norvegica 1 f simplex . . a truncata . . f Centropages calaninus . . 2 Copilia quadrata 1 Corycaeus crassiusculus f c longistylis c c speciosus c c typicus . . f Eucalanus attenuatus . . c crassus . . f Euchaeta acuta . . 1 marina . . f Euchirella pulchra . . 2 Farranula carinata a c curta . . f gibbula c rostrata a c Labidoccra detruncata f Lubboclcia squiUimana. . . Lucicutia flavicornis Mecynocera clausi Megacalanus longicornis. Microcalanus pusillus. . . . pygmaeus Microsetella rosea Neocalanus robustior. . . Oithona attenuata plumifera similis Oncaea conifera minuta venusta Pachos punctatum Paracalanus parvus Pontellina plumata Pseudocalanus minutus. Rhincalanus cornutus. . . nasutus Sapphirina auronitens. . . metallina Scolecithrix danae Temora discaudata Undeuchaeta plumosa. . Undinula darwinii f 2 f c 1 f c f f 4 f 2 c a 2 c 5 c f f 1 1 a 3 Again the temperature, salinity, and hydrogen-ion concen- tration were high and did not change. Twenty species were found in the surface tow and 48 in the SO-meter net. Thirt>'- six species (70 per cent) were present in one tow and not in the other, and 16 species were found in both tows. The 50- meter tow was four and a half times as long as the surface tow but had only twice the volume. The same genera as at station 81, together with many others, were confined to the deeper tow, and the same genera were divided between the two tows. Only a single specimen of Candacia was present at the surface, all the others of the 4 species of this genus appearing only in the SO-meter tow. Contrary to expectation, the single specimen of Undeuchaeta was found at the surface rather than in the deeper tow. 102 COPEPODS OF LAST CRUISE OF CARNEGIE Station 83 March 2, 1929; 17° 00' S, 129° 45' W; bottom depth, 3966 m; 31 species Depth of tow, m Temperature, °C Salinity, o/oo Volume of tow, cm' 50 Depth of tow, m 50 27.5 27.4 Density (utp^ 23.5 23.9 36.2 36.4 Hvdrogen-ion concentration fpH) 8.24 8.24 32 64 Length of tow, miles 0.1 0.3 Acartia danae . • f Acrocalanus gracilis . . r Calocalanus pavo 2 Candacia simplex c Centropages calaninus . . 2 Copilia quadrata . • 3 Corycaeus crassiusculus f c dubius f pacificus . . f speciosus f 2 Euchaeta acuta r marina 1 c Euchirella curticauda . . 2 Farranula carinata a a rostrata a Labidocera detruncata c Macrosetella gracilis Mecynocera clausi Megacalanus longicornis . Microcalanus pygniaeus. Microsetella rosea Neocalanus gracilis robustior Oithona attenuata similis spinirostris Oncaea venusta Paracalanus parvus Pontellina plumata Pseudocalanus minutus. , Scolecithrix danae The temperature, salinit>-, and hydrogen-ion concentration were all high and practically unchanged at the two depths. Eleven species appeared at the surface and 27 species in the SO-meter tow. Twenty-four species (75 per cent) were found in one tow and not in the other, and 7 species were present in both tows. Euchirella and Megacalanus were found only in the deeper tow; the other four deep-water genera did not occur at all in this locality. Corycaeus and Farranula were divided as before between the two tows, and the 2 species of Farranula constituted a large percentage of the surface tow, but Oithona, except for 2 specimens, and Oncaea were not present at the surface. Station 84 March 4, 1929; 17° 11' S, 133° 18' VV; bottom depth, 4121 m; 37 species Depth of tow, m Temperature, °C Salinity, o/oo Volume of tow, cm' 50 Depth of tow, m 50 27. S 27.5 Density (', and h>drogen-ion concentration were all high and changed ver^- little. Twelve species were found at the surface and 31 in the 50-meter tow. Thirty-one species (84 per cent) were present in one tow and not in the other, and 6 were found in both tows. Cnrycaeiis, Oithona, and Oncaea were much more abundant in the deeper tow; Far- ranula was divided between the two tows, but more abundant at the surface, where it formed a large percentage of the total. Station 85 March 6, 1929; 17° 12' S, 136° 37' \V; bottom depth, 3791 m; 35 species Depth of tow, m Temperature, °C Salinity, 0/00 Volume of tow, cm' 50 Depth of tow, m 50 27.9 27.8 Density (ctip) 23.3 23.5 36.2 36.2 Hydrogen-ion concentration (pH) 8.22 8.22 36 64 Length of tow, miles 0.1 0.4 Acartia danae . . c Acrocalanus gracilis 1 monachus . . f Calanus minor . . f Candacia bispinosa . . a simplex • . a Copilia denticulata . . 1 Corycaeus crassiusculus r c dubius 2 speciosus . . c Eucalanus attenuatus . . f elongatus . . f Euchaeta marina . . a Euchirella curticauda . . 3 Farranula carinata a a gibbula 2 rostrata a r Megacalanus longicornis . . a Microcalanus pygmaeus. Microsetella rosea Neocalanus gracilis robustior Oithona attenuata similis spinirostris Oncaea minuta Paracalanus parvus Phaenna spinifera Pleuromamma gracilis. . Pontellina plumata Pseudocalanus minutus . Sapphirina angusta pyrosomatis Scolecithrix danae Undinula darwinii The temperature, salinity, and hydrogen-ion concentration were all high and unchanged at the two depths. Eight species were present at the surface and 31 in the 50-meter tow. Thirty-one species (90 per cent) were present in but one of the tows and only 4 were present in both tows. Oithona and Oncaea were confined to the deeper tow, but Corycaeus and Farranula were divided between the two tows. Candacia, Eucalanus, and Neocalanus, with many others, were found only at SO meters. The surface tow contained very few spec- imens besides the 2 species of Farranula recorded as abundant. Between stations 85 and 86 March 8, 1929; 17° 48' S, 140° 49' W; 20 species Acartia danae c Acrocalanus gracilis 1 Candacia norvegica 5 simplex f Centropages calaninus f Corycaeus agilis r crassiusculus c Corycaeus longistylis 2 robustus 2 speciosus f Farranula carinata c gibbula 4 rostrata c Microsetella rosea 1 Oncaea minuta f similis 2 venusta c Paracalanus parvus c Pseudocalanus minutus c Sapphirina auronitens 1 Volume of tow, 32 cm'; length, 3 miles; surface only. In this nocturnal tow between stations, 20 copepod species were found, including many that were confined to the deeper tow at the regular station on either side. None of the species was at all abundant, but 7 out of the 20 were recorded as common. 104 COPEPODS OF LAST CRUISE OF CARNEGIE Station 86 March 9, 1929; 17° 36' S, 141° 55' W; bottom depth, 2132 m; 35 species Depth of tow, m Temperature, °C Salinity, o/oo \'olume of tow, cm' 50 Depth of tow, m 28.2 27.4 Density (fftp) 36.1 36.2 Hydrogen-ion concentration (pH) 32 34 Length of tow, miles 50 23.2 23.7 8.29 8.29 0,1 0.2 Acartia danae Acrocalanus gracilis monachus Calocalanus styliremis. . . . Candacia simplex Centropages calaninus. . . . Clausocalanus arcuicornis. Copilia denticulata quadrata Corycaeiis crassiusculus. . . longistylis speciosus typicus Euchaeta acuta niarina Farranula carinata concinna rostrata Lubbockia squilhmana. . Microsetella rosea Neocalanus gracilis Oithona plumifera similis spinirostris Oncaea media minuta venusta Paracalanus parvus. . . . Phaenna spinifera Pleuromamma gracilis. . Pseudocalanus minutus. Sapphirina auronitens. . metallina pyrosomatis Scolecithrix danae 1 f f f c f c c a c 4 c c 2 1 19 f Again the temperature, salinit>", and h)-drogen-ion con- centration were high and almost the same for both depths. Only 5 species were found at the surface, and 34 in the 50- meter tow. Thirty-one species (90 per cent) appeared in one tow and not in the other, and only 4 were common to both. The surface tow j'ielded but 4 specimens besides the 2 species of Farranula. The 50-meter tow contained a single female of Sapphirina pyrosomatis, found in only two other localities. Station 87 March 11, 1929; 18° 05' S, 145° 33' VV; bottom depth, 4315 m; ii species Depth of tow, m Temperature, °C Salinity, o/oo \olume of tow, cm' 50 Depth of tow, m 50 27.8 26.5 Density (o-tp) 23.2 23.9 36.0 36.0 Hydrogen-ion concentration (pH) 8.28 8.26 34 64 Length of tow, miles 0.4 0.9 Acartia danae Acrocalanus gracilis Calanus minor Candacia simplex Centropages calaninus. . . . Clausocalanus arcuicornis. Corycaeus crassiusculus. . . longistylis speciosus typicus Euchaeta acuta marina Farranula carinata gibbula rostrata Mecynocera clausi Microcalanus pygniaeus. . Microsetella rosea Miracia efferata Neocalanus gracilis robustior Oithona attenuata similis spinirostris Oncaea minuta venusta Paracalanus parvus pygniaeus Pleuromamma gracilis. . Pseudocalanus minutus. Scolecithrix danae Spinocalanus caudatus. . magnus The temperature, salinity, and hydrogen-ion concentration were high and changed but little at the two depths. Eight species were found at the surface and 31 in the SO-meter tow. Twenty-seven species (89 per cent) were found at one depth onh- and 6 at both depths. In the surface tow Farratiiila cari- nata exceeded in abundance all the other species combined, and in the 50-meter tow Pseudocalanus minutus was the most abundant single species. LISTS UF SPECIES BY STATIONS 105 Station 88 March 21, 1929; 16° 42' S, 150° 41' \V; bottom depth, 3697 in; 53 species Depth of tow, m Temperature, °C Salinity, 0/00 Volume of tow, cm' 50 28.4 28.4 35.8 35.8 34 96 Depth of tow, m 50 Density (-two species (80 per cent) were present in one tow and not in the other, and 5 were found in both tows. Corycaeus and Farranula were well di\ ided between the two tows; Oithona and Oncaea were both found only in the 50-meter tow. no COPEPODS OF LAST CRUISE OF CARNEGIE Station 93 March 31, 1929; 14° 41' S, 167° 41' W; bottom depth, 5208 m; 56 species Depth of tow, ni Temperature, °C SaHnity, o/oo Volume of tow, cm' 50 Depth of tow, m 50 28.7 28.5 Density (o-tp) 21 9 22.3 34.7 34.7 Hvdrogen-ion concentration (pH) 8.30 8.30 32 32 Length of tow, miles 0.2 0.3 Acartia danae Acrocalanus gibber f gracilis a longicornis f monachus , Calanus minor f Calocalanus pavo plumulosus styliremis Candacia bispinosa norvegica simplex truncata Centropages calaninus Clausocalanus arcuicornis Corycaeus andrewsi f clausi 2 crassiusculus f giesbrechti longistylis ovalis pacificus pumilus speciosus Eucalanus attenuatus elongatus Euchaeta marina Euchirella brevis Euchirella curticauda Farranula carinata a gibbula f rostrata a Labidocera detruncata Macrosetella gracilis 1 Microcalanus pygmaeus Microsetella rosea Neocalanus gracilis Oithona attenuata brevicornis similis , spinirostris Oithonina nana 2 Oncaea minuta f tenella venusta c Paracalanus parvus f Pontella tenuiremis f Pontellina plumata Pseudocalanus minutus f Sapphirina auronitens nigromaculata Scolecithricella minor Scolecithrix danae Temora discaudata Undinula darwinii vulgaris The temperature and hydrogen-ion concentration were high, the salinity a little lower, but all three remained about the same at the two depths. Nineteen species were found at the surface and 49 in the 50-meter tow. Forty-four species (80 per cent) were confined to one of the two tows and 12 were found in both tows. Corycaeus and Oithona were more abundant in the deeper tow, the latter not appearing at all at the surface. Farranula and Oncaea were about evenly divided between the two tows. Only one Candacia {simplex) appeared at the surface, the others only in the SO-meter net. Off Samoa 15 species Acartia danae f Calanopia elliptica a Calanus minor f propinquus 1 Calocalanus styliremis 2 Candacia simplex 2 Canthocalanus pauper 1 Microcalanus pygmaeus 2 Oithona plumifera 2 spinirostris 1 Oncaea media r minuta f ornata 5 9 Paracalanus parvus f I'ndinula \'ulgaris a Every one of the IS species obtained in this surface tow was as distinctly pelagic as those captured in the open ocean. The littoral copepods of these oceanic islands do not seem to venture very far into the surrounding ocean. On the contrary. the pelagic copepods come in \ery close to the shore, cspecialh' at the surface. Undinula and Calanopia made up about 90 per cent of this tow, each of the other genera being confined to a few specimens. LISTS OF SPECIES BY STATIONS III Station 94 April 22, 1929; 12° 47' S, 171° 35' W; bottom depth, 4760 m; 64 species Depth of tow, 111 Temperature, °C Salinity, o/oo \oluiiie of tow, cm' 50 100 1 )epth of tow, m SO 100 29.4 2y.3 28.. S Density (cr,p) 21.7 22,0 23. 1 34.7 34.7 35 . 5 Hvdrogen-ion cone. (pH) 8.25 8.25 8.21 34 48 80 Length of tow, miles 1.0 1.2 1.3 Acartia danae negligens Acrocalanus gracilis longicornis monachus Calanus minor Calocalanus pavo Candacia bispinosa norvcgica simplex truncata Canthocalanus pauper Centropages calaninus Clausocalanus arcuicornis Clytemnestra scutellata Copilia denticulata quadrata Corycaeus agilis crassiusculus lautus longistylis pumilus speciosus typicus Danodes plumata, n. gen. and n. sp. Eucalanus attenuatus crassus elongatus Euchaeta marina Farranula carinata carta gibbula Farranula rostrata Haloptilus longicornis. . . . spiniceps . . Heterorhabdus papilliger. Lubbockia squiUimana. . . Lucicutia flavicornis Macrosetella oculata Mecynocera clausi INIicrocalanus pusillus. . . . pygmaeus Microsetella rosea Neocalanus gracilis Oithona attenuata plumifera setiger similis spinirostris Oncaea media mediterranea minuta venusta Paracalanus parvus Pontellina plumata Pseudocalanus niinutus. . Sapphirina angusta auronitens nietallina nigromaculata Scolecithrix danae llndinula darwinii vulgaris \ ettoria granulosa Temperature high, diminishing only about 1° in the 100 meters; salinity moderate, increasing nearly- 1 point at the 100-meter depth; hydrogen-ion concentration fairl>" high, changing scarcely at all. Eight species were found at the surface, 39 in the 50-meter tow, and 46 in the 100-meter tow. Thirty-six species (56 per cent) were confined to a single tow and on!\' 3 were present in all three tows. Corycaeus and • Farranula were well distributed in depth and included the 3 species just mentioned, no other genus appearing at all the depths. Candacia and Oncaea were most abundant in the 50- meter tow, and Oithona in the 100-meter tow. The 100-meter tow was 30 per cent longer than the suface tow and 10 per cent longer than the 50-meter tow, but its proportionate N'olume was considerably greater. 112 COPEPODS OF LAST CRUISE OF CARNEGIE Station 95 April 24, 1929; 8° 43' S, 170° 56' VV; bottom depth, 4298 m; 74 species Depth of tow, m Temperature, °C Salinity, o/oo Volume of tow, cm' SO 100 Depth of tow, m 29.3 28.5 Density (-one species (55 per cent) were present in one tow and absent from the other, and 33 were found in both tows. The 100- meter tow contains one of the few records for Amallothrix propinqua. Candacia, Corycaeus, Farranula, Oithona, and Oncaea were each well di\ided between the two tows. Between st.\tions 95 .\nd 96 April 25, 1929; 7° 59' S, 171° 49' VV; 16 species Acrocalanus gibber f gracilis c monachus f Calanus minor c Calocalanus plunmlosus 1 Candacia simplex a Centropages calaninus 1 Corycaeus crassiusculus f speciosus 2 Euchaeta acuta 4 Farranula carinata f Farranula rostrata f Oithona plumifera 1 similis 2 Paracalanus parvus c Pseudocalanus minutus c This surface tow yielded 16 species, but most of the tow was made up of development stages of Candacia simplex. LISTS OF SPECIES BY STATIONS "3 Station 96 April 26, 1929; 6° 47' S, 172° 23' \V; bottom depth, 5269 m; 68 species Depth of tow, m Temperature, °C Salinity, o/oo X'olume of tow, cm' 50 100 Depth of tow, m 50 100 29.3 29.2 28.2 Density (o-tp) 22.1 22.4 23.2 35.2 35.2 35.6 Hvdrogen-ion cone. (pH) 8.23 8.23 8.19 48 64 64 Length of tow, miles 0.9 1.2 1.2 Acartia danae negligens Acrocalanus gracilis longicornis monachus Amallothrix obtusifrons. . . Calanus minor Calocalanus pavo Candacia bispinosa norvegica simplex truncata Centropages calaninus . . . . Clausocalanus arcuicornis. Clytemnestra rostrata. ... scutellata Copilia denticulata vitrea Corycaeus catus crassiusculus dubius giesbrechti limbatus longistylis pumilus speciosus typicus Eucalanus attenuatus crassus elongatus Euchaeta marina Farranula carinata curta gibbula 2 c c f 2 4 f a c 2 2 c c f f c a a c f 2 f f f f 1 2 f 4 2 f 1 c c r 2 r f f 2 f f f f f 1 c f c a a 3 f c Farranula rostrata Haloptilus longicornis. . . spiniceps Heterorhabdus papilliger. Lubbockia squillimana. . . Lucicutia clausii flavicornis Macrosetella gracilis oculata Microcalanus pusiUus. . . . pygmaeus Microsetella rosea Neocalanus gracilis robustior Oithona attenuata plumifera similis spinirostris Oncaea media niinuta similis venusta Paracalanus parvus Phaenna spinifera Pontella tenuiremis Pontellina plumata Pseudocalanus minutus. . Sapphirina auronitens. . . nigromaculata Scolecithricella minor. . . . Scolecithrix danae Undinula caroli darwinii V'ettoria granulosa The temperature was high and dropped 1° at a depth of 100 meters; the salinity rose and the hydrogen-ion concentra- tion fell, both \ery slightly. Seventeen species were found at the surface, 41 in the SO-meter tow, and 50 in the 100-meter tow. Thirty-nine species (56 per cent) were each confined to a single tow and 10 were found in all three tows. Corycaeus, Farranula, and Oncaea were well di\ided among the three tows, but Oithona did not appear at all at the surface. Three of the Candacia species, Eucalanus, Euchaeta, and Undinula were present onl>- in the two deeper tows; Haloptilus, Hetero- rhabdus, Lubbockia, and Lucicutia were confined to the 100- meter tow. The 50-meter and 100-meter tows were each 3i per cent longer than the surface tow and their proportionate \olume corresponded exactly. 114 COPEPODS OF LAST CRUISE OF CARNEGIE Station 97 April 28, 1929; 3° 47' S, 172° 39' \V; bottom depth, 5253 m; 74 species Depth of tow, m Temperature, °C Salinity, o/oo \'olume of tow, cm^ 50 100 Depth of tow, m 50 100 28.3 28.0 27.6 Density (o-tp) 22.4 22.9 23.4 35.1 35.3 35.5 Hydrogen-ion cone. (pH) 8.16 8.16 8.15 32 36 80 Length of tow, miles 0.5 0.6 0.6 Acartia danae negligens Acrocalanus gibber gracilis longicornis monachus Calanus minor tonsus Calocalanus pavo Candacia bispinosa simplex truncata Canthocalanus pauper. . . . Centropages calaninus . . . . Clausocalanus arcuicornis. Clytemnestra scutellata. . . Copilia denticulata quadrata Corycaeus agilis catus crassiusculus lautus longistylis lubbockii speciosus typicus Eucalanus attenuatus crassus elongatus Euchaeta acuta marina Euchirella brevis Farranula carinata concinna gibbula rostrata Haloptiliis longicornis. ... a f f a c c f c f c 2 c c 1 2 5 2 f 2 f f c f f 2 f f 2 1 f 4 2 3 r c c c r f f 2 3 c f f f f 2 1 5 f f f a c 4 1 c c Haloptilus spiniceps Heterorhabdus papilliger. Labidocera detruncata. . . Lucicutia flavicornis longicornis Macrosetella gracilis Mecynocera clausi Megacalanus longicornis. Microcalanus pusillus. . . . pygmaeus Microsetella norvegica. . . rosea Miracia efTerata Neocalanus gracilis robustior tenuicornis Oithona attenuata plumifera similis spinirostris Oncaea curta mediterranea minuta similis venusta Paracalanus parvus Pontella tenuiremis Pontellina plumata Pseudocalanus minutus. . Sapphirina angusta auronitens metallina nigromaculata ovatolanceolata Scolecithrix danae Undinula caroli darwinii The temperature, salinity, and h>drogen-ion concentration were high and changed very little in the 100 meters. Twenty- nine species were found at the surface, 51 in the 50-meter tow, and 45 in the 100-meter tow. Thirty-six species (49 per cent) were each confined to a single tow and 13 were present in all three tows. Corycaeus, Farranula, and Oncaea were divided among the three tows, but Eucalanus, Euchirella, Oithona, and Undinula were found only in the two deeper tows. The surface tow contained one of the two records for Sapphirina ovatolanceolata; the other 4 species of Sapphirina were found, with one exception, in the two higher tows. The two deeper tows were each 20 per cent longer than the sur- face tow; the volume of the 50-meter tow was 10 per cent larger, but that of the 100-meter tow was 150 per cent larger. LISTS OF SPECIES BY STATIONS "5 Station 98 April 30, 1929; 0° 18' X, 173° 59' W; bottom depth, 5599 m; 72 species Depth of tow, m Temperature, °C Sahnity, o/oo Volume of tow, cm^ 50 100 Depth of tow, m 50 100 27.0 26.9 20.7 Density (Vtp) 22.9 23.2 li . 5 35.2 35.3 35.-1 Hydrogen-ion cone. (pH) 8.16 8.16 8.14 48 80 96 Length of tow, miles 1.3 1.3 1.3 Acartia danae Acrocalanus gibber gracilis longicornis monachus Calanus minor tonsus Calocalanus plumulosus. . . Candacia bispinosa longimana nor\'egica simplex truncata Canthocalanus pauper. . . . Centropages calaninus . . . . Clausocalanus arcuicornis . Clytemnestra rostrata. . . . scutellata Copilia denticulata quadrata Corycaeus crassiusculus. . . f urcifer longistylis pumilus robustus speciosus typicus Eucalanus attenuatus elongatus Euchaeta acuta marina Euchirella brevis F"arranula carinata curta gibbula gracilis Farranula rostrata Haloptilus longicornis. . Labidocera detruncata. . Lucicutia clausii Macrosetella gracilis. , . , oculata Mecynocera clausi Microcalanus pusillus. . . pygmaeus Microsetella rosea Neocalanus gracilis robustior Oithona attenuata fallax plumifera similis spinirostris Oncaea conifera media minuta venusta Pachos punctatum tuberosum Paracalanus parvus Pontellina plumata Pontellopsis armata. . . . Pseudocalanus minutus. Rhincalanus cornutus. . . Sapphirina angusta auronitens metallina nigromaculata opalina Scolecithrix danae Undinula caroli darwinii a c 29 a 2 2 The temperature, salinity, and h\drogen-ion concentration showed but little variation at the three depths. Thirty-two species were found at the surface, 51 in the 50-meter tow, and 41 in the 100-meter tow. Thirt\-se\en species (50 per cent) were each confined to a single tow and 16 were present in all three tows. Corycaeus, Oithona, Oncaea, and Sapphirina were well distributed at all three depths, but Farranula did not appear at all in the deepest tow. Candacia, Euchaeta, and Undinula were confined to the two deeper tows. The surface tow contained the only record for Pontellopsis armata and the 50-meter tow' one of the very few records for Pachos tuberosum. The three tows were of exactly the same length, but the volume of the 50-meter tow was 66 per cent, and of the 100-meter tow 100 per cent, larger than that of the surface tow. About one-quarter of the abundance records are expressed in numerals from 1 to 5, but in the other three- quarters enough species are designated as abundant or com- mon to more than offset this scarcit\-. [i6 COPEPODS OF LAST CRUISE OF CARNEGIE Station 99 May 2, 1929; 4° 22' N, 176° 23' VV; bottom depth, 4951 m; 52 species Depth of tow, m Temperature, °C Sahnity, o/oo \'olume of tow, cm' 50 100 Depth of tow, m 50 100 27.9 27.8 27.8 Density (cr,p) 22.3 22.6 22.9 34.9 34.9 35.0 Hydrogen-ion cone. (pH) 8.21 8.22 8.22 48 48 80 Length of tow, miles 0.5 0.5 0.7 Acartia danae Acrocalanus gibber gracilis longicornis nionachus Calocalanus pavo plumulosus Candacia bispinosa norvegica truncata Canthocalanus pauper. . . . Centropages calaninus. . . . Clausocalanus arcuicornis . Clytemnestra rostrata. ... scutellata Copilia quadrata Corycaeus anglicus crassiusculus limbatus pumilus speciosus Eucalanus attenuatus elongatus Euchaeta acuta marina Euchirella messinensis. . . Farranula carinata gibbula rostrata Labidocera detruncata. . Lucicutia flavicornis. . . . Macrosetella gracilis. . . . Microcalanus pusillus. . . pygmaeus Microsetella rosea Neocalanus gracilis robustior Oithona atteauata pluniifera similis Oncaea media minuta venusta Paracalanus parvus Pontellina plumata Pseudocalanus minutus. Sapphirina auronitens. . nigromaculata scarlata Scolecithri.v danae Undinula caroli darwinii The temperature, salinity, and hydrogen-ion concentration changed very little at the three depths. Nineteen species were found at the surface, 32 at the 50-meter depth, and 39 at the 100-meter depth. T\venty-fi\e species (47 per cent) were each confined to a single depth and 10 were present at ail three depths. Candacia, Corycaeus, Oithona, and Oncaea were largely confined to the two lower depths, and Farranula was more abundant at the surface. Canthocalanus, Centro- pages, Eucalanus, and Euchaeta were among those appearing at all three depths; Sapphirina was found at the surface and in the 100-meter tow, but was entirely absent from the 50- meter tow. The 100-meter tow was 40 per cent longer than each of the other two tows, but its volume was 66 per cent larger. LISTS OF SPECIES BY STATIONS 117 Station 100 May 4, 1929; 8° 05' N, 178° 48' W; bottom depth, 5800 m; 50 species Depth of tow, m Temperature, °C Salinity, 0/00 Volume of tow, cm^ .SO 100 Depth of tow, m .SO 100 27.7 27.6 27.6 Density (' increased, and the hydrogen-ion concentration decreased in the 100 meters, each but very little. Sixteen species were taken at the surface, 33 in the 50-meter tow, and 29 in the 100-meter tow. Twenty- four species (54 per cent) were each confined to a single depth and 12 were present at all three depths. Corycaeus, Farranula, and Oithona were well distributed at all three depths. Candacia and Oncaea were confined to the two deeper tows. These latter tows were a little longer than the one at the surface and their volume was 50 per cent larger. 120 COPEPODS OF LAST CRUISE OF CARNEGIE Station 103 May 11, 1929; 19° 19' N, 166° 23' E; bottom depth, 3708 m; 50 species Depth of tow, m Temperature, °C Salinity, o/oo Vohiine of tow, cm' 50 100 Depth of tow, m 50 100 26.0 25.8 24.7 Density (wtp) 23.0 23.4 24.0 34.9 35.1 35 . 2 Hydrogen-ion cone. (pH) 8.25 8.25 8.25 36 35 M Length of tow, miles 0.5 0,4 0.5 Acartia danae Acrocalanus gracilis longicornis monachus Calanus minor Calocalanus pavo plumulosus Candacia bispinosa longimana simplex Canthocalanus pauper. . . . Clausocalanus arcuicornis. furcatus Clytenmestra scutellata. . . Copilia denticulata quadrata Corycaeus clausi crassiusculus robustus speciosus Euchaeta marina Farranula carinata gibbula rostrata Haloptilus longicornis Heterorhabdus spinifrons. . . . Labidocera detruncata Mecynocera clausi Microcalanus pusillus pygmaeus Microsetella rosea Neocalanus gracilis robustior Oithona attenuata similis spinirostris Oncaea curta media minuta venusta Onchocalanus nudipes, n. sp. Paracalanus parvus Pontellina plumata Pseudocalanus minutus Sapphirina angusta auronitens metallina nigromaculata Scolecithrix danae Undinula darwinii The temperature decreased a triHe more than 1° in the 100 cent) were each confined to a single depth and 5 were found meters; the salinity increased less than half a point, and the at all three depths. Corycaeus, Oithona, and Oncaea were hydrogen-ion concentration remained constant. Twelve found onI\- in the two deeper tows and Farranula at all three species were obtained at the surface, 3i in the SO-meter tow, depths; Sapphirina was more numerous in the two deeper and 39 in the 100-meter tow. Twenty-two species (44 per tows. The three tows were about equal in length and volume. LISTS OF SPECIES BY STATIONS 121 Station 104 May 13, 1929; 20° 12' N, 161° 19' E; bottom depth, 4741 m; 58 species Depth of tow, m Temperature, °C Salinity, o/oo X'olume of tow, cm' 50 ion Depth of tow, m 50 100 26.1 25.8 25.3 Density (crtp) 23.1 23.5 23.9 35.1 35.2 35.3 Hydrogen-ion cone. (pH) 8.24 8.24 8.21 64 64 48 Length of tow, miles 1.4 1.3 1.4 Acartia danae f Acrocalanus gibber gracilis a Calocalanus pavo 2 [)luniiil()sus Candacia bispinosa f norvegica simplex truncata f varicans Centropages calaninus f Clausocalanus arcuicornis f Copilia denticulata f quadrata Corycaciis catus crassiusculiis furcifer longistylis pumilus speciosus typicus Eucalanus attenuatus Euchacta marina Farranula carinata a gibbula f gracilis r rostrata a Haloptilus acutifrons longicornis Heterorhabdus papilliger Labidocera detruncata c Lucicutia clausii flavicornis Macrosetella gracilis 1 Mecynocera clausi Megacalanus longicornis Microcalanus pusillus pygmaeus 2 Microsetella norvegica 2 rosea Neocalanus gracilis robustior Oithona attenuata similis spinirostris Oncaea media r minuta similis venusta f Paracalanus parvus f PIcuromamma gracilis Pontellina plumata 1 Pseudocalanus minutus f Sapphirina angusta 1 auronitens c nigromaculata Scolecithrix danae Undinula darwinii The temperature and hydrogen-ion concentration de- creased slightly and the salinity increased a trifle in the 100 meters. Twenty-five species were taken at the surface, 35 in the 50-meter tow, and 34 in the 100-meter tow, an exceptional \ertical distribution. Thirty-two species (55 per cent) were each confined to a single depth and 10 were found at all three depths. Candacia, Corycaeus, Farranula, and Oncaea were found at all depths, but Oithona did not appear at the sur- face. Haloptilus, Pleiiromamma. Heterorhabdus, and Lucicutia were found only at 100 meters. The three tows were of prac- tically the same length, but the volume of each of the two upper tows was one-third larger than that of the 100-meter. 122 COPEPODS OF LAST CRUISE OF CARNEGIE Station 105 May 15, 1929; 18° 43' N, 156° 16' E; bottom depth, 5576 m; 54 species Depth of tow, m Temperature, °C Sahnity, o/oo Volume of tow, cm' 50 100 Depth of tow, m 50 100 26.9 26.8 25.2 . Density (irtp) 22.7 22.9 23.8 34.9 34.9 35.1 Hydrogen-ion cone. (pH) 8.23 8.23 8.23 32 35 33 Length of tow, miles 2.0 2.0 2.1 Acartia danae 2 Acrocalanus gibber gracilis f longicornis monachus Calanus minor Calocalanus pavo Candacia bispinosa norvegica truncata varicans Canthocalanus pauper Centropages calaninus 1 Copilia denticulata 1 quadrata Corycaeus crassiusculus c limbatus pumilus speciosus f typicus Euchaeta marina Farranula carinata a curta r gibbula c rostrata a Haloptilus longicornis Labidocera detruncata 1 Lubbockia squillimana. . Lucicutia clausii flavicornis Macrosetella gracilis. . . . Microcalanus pusillus. . . pygmaeus Microsetella norvegica. . rosea Neocalanus gracilis robustior tenuicornis Oithona attenuata plumifcra similis Oncaea conifera media minuta venusta Paracalanus parvus Phaenna spinifera Pontellina plumata Pseudocalanus minutus. Sapphirina auronitens. . nigromaculata stellata Scolecithrix danae Undinula darwinii The temperature diminished 1?5 in the 100 meters, the salinity increased a trifle, and the hjdrogen-ion concentration remained the same. Fourteen species were taken at the sur- face, 31 in the 50-meter tow, and 38 in the 100-meter tow. Thirty-three species (60 per cent) were each confined to a single depth and 8 were found at all three depths. Corycaeus and Farranula were distributed at all three depths. Candacia, Oithona, and Oncaea did not appear at all in the surface tow. Paracalanus was evenly divided among the three tows, and Pseudocalanus appeared only in the 100-meter tow. Both the length and the volume of the three tows were practically the same. LISTS OF SPECIES BY STATIONS 123 Station 106 May 17, 1929; 16° 14' N, 151° 04' E; bottom depth, 5925 m; 68 species Depth of tow, m Temperature, °C Salinity, o 00 Volume of tow, cm' 50 100 Depth of tow, m 50 100 27.2 26.0 25.5 Density (o-tp) 22.6 22.9 23.7 34.9 34.9 35.0 Hydrogen-ion cone. (pH) 8.23 8.23 8.23 64 64 48 Length of tow, miles 0.5 0.5 0.5 Acartia danae Acrocalanus gibber gracilis longicornis monachus Calanus minor Calocalanus pavo plumosus styliremis Candacia bispinosa longimana simplex truncata varicans Canthocalanus pauper. . . . Centropages calaninus . . . . Clausocalanus arcuicornis . Clytemnestra scutellata. . . Copilia denticulata Corycaeus clausi crassiusculus dubius ovalis pacificus speciosus Eucalanus attenuatus elongatus Euchaeta acuta marina Farranula carinata gibbula gracilis rostrata Haloptilus longicornis. . . . Haloptilus plumosus spiniceps Hcterorhabdus papilliger. . . . Labidocera detruncata Lubbockia squillimana Lucicutia clausii Mecynocera clausi Megacalanus longicornis. . . . Microcalanus pusillus pygmaeus Microsetella rosea Miracia eflerata Ncocalanus gracilis robustior Nesippus sp Oithona attenuata plumifera similis spinirostris Oncaea minuta venusta Onchocalanus nudipes, n. sp. Paracalanus aculeatus parvus Phaenna spinifera Pontella tenuiremis Pontellina plumata Pseudocalanus minutus Sapphirina auronitens metallina nigromaculata opalina Scolecithrix danae Undinula darwinii Icf The temperature decreased nearly 2° in the 100 meters, the salinity and hydrogen-ion concentration remaining practically the same. Thirt\' species were found at the surface, 35 in the 50-meter tow, and 45 in the 100-meter tow. Thirty-six species (53 per cent) were each confined to a single depth and the three tows was exactly the same, the \olume of each of the two upper tows was 33 per cent greater than that of the 100-meter tow. Corycaeus, Farranula, and Oiicaea were dis- tributed at all three depths, together with Eucalanus, Eu- chaeta, and Sapphirina. None of the 4 species of Oithona or 10 were present at ail three depths. Although the length of the 5 species of Candacia appeared at the surface. 124 COPEPODS OF LAST CRUISE OF CARNEGIE Station 107 May 19, 1929; 14° 05' N, 146° 06' E; bottom depth, 4920 m; 61 species Depth of tow, m Temperature, °C Salinity, o/oo \'okime of tow, cm' SO 100 Depth of tow, m 50 100 28.4 26.7 25.2 Density (o-tp) 21.9 22.2 23.1 35.0 34.9 34.9 Hydrogen-ion cone. (pH) 8.23 8.23 8.23 32 32 32 Length of tow, miles 1.1 0.5 0.5 Acartia danae Acrocalanus gibber gracilis longicornis monachus Calanus minor Calocalaniis pavo plumulosus Candacia bispinosa simplex truncata varicans Canthocalanus pauper. . . . Centropages calaninus. . . . Clausocalanus arcuicornis. Clytemnestra scutellata. . . Copilia denticulata quadrata vitrea Corycaeus agilis crassiusculus flaccus lautus longistylis pacificus speciosus Euchaeta acuta marina Euchirella brevis Farranula carinata gibbula Farranula gracilis rostrata Haloptilus plumosus spiniceps Heterorhabdus papilliger. Lubbockia squillimana. . . Lucicutia clausii flavicornis Mecynocera clausi Microcalanus pusillus. . . . pygmaeus Microsetella rosea Neocalanus gracilis robustior Oithona attenuata similis spinirostris Oncaea curta media minuta notopa venusta Paracalanus parvus Pontcllina plumata Pseudocalanus minutus. . Sapphirina auronitens. . . nigromaculata Scaphocalanus elongatus. Scolecithrix danae Undinula darwinii f 2 c c 2 f 2 19 f c The temperature fell 3° in 100 meters, the salinity and hydrogen-ion concentration remaining constant. There were 15 species at the surface, 37 in the 50-meter tow, and 44 in the 100-meter tow. Thirty-four species (56 per cent) were each confined to a single depth and 8 were present at all three depths. Although the surface tow was more than twice the length of either of the other tows, its yolume was exactly the same. Corycaeus, Euchaeta, Farranula, and Oncaea were dis- tributed in all three tows, but Candacia, Oithona, and Sap- phirina appeared only in the two deeper tows. Here again the paucity of species at the surface compared with those at the other two depths indicates strong light before the tows were taken. The surface tow contained a \er>- large number of 2 of the Farranula species. LISTS OF SPECIES BY STATIONS 125 Station 108 May 27, 1929; 18° 26' .\, 144° 01' E; bottom depth, 3573 m; 57 species Depth of tow, m Temperature, °C Salinity, 0/00 \'olume of tow, cm' 50 100 Depth of tow, m 50 100 28.4 20.7 25.2 Density (utp) 22.2 23.0 23.7 35.0 34.9 34.9 Hvdrogen-ion cone. (pH) 8.25 8.25 8.23 32 32 i2 Length of tow, miles 0.8 1.0 1.1 Acrocalanus gibber. . . . gracilis Aetideus armatus Calanus minor Calocalanus pavo Candacia bispinosa. . . . longimana simplex truncata varicans Canthocalanus pauper. Copilia dcnticulata. . . . quadrata recta vitrea Corycaeus agilis catus crassiusculus furcifer limbatus ovalis speciosus Eucalanus attenuatus. . Euchaeta marina Farranula carinata. . . . concinna gibbula rostrata Haloptilus longicornis. Heterorhabdus papilliger. . Lubbockia squillimana. . . . Lucicutia clausii fla\icornis Macrosetella gracilis Mecynocera clausi Megacalanus longicornis. . Microcalanus pusillus pygmaeus Microsetella rosea Neocalanus gracilis robustior Oithona attenuata plumifera similis spinirostris Oncaea conifera media minuta venusta Paracalanus parvus Phaenna spinifera Pontellina plumata Pseudocalanus minutus. . . Sapphirina nigromaculata. stellata Scolecithrix danae Undinula darwinii 5 2 c c 3 1 3 1 f f f f f f 3 c c f Again the high surface temperature fell 3° in 100 meters, but the salinity and h\drogen-ion concentration remained nearly constant. Si.\teen species were taken at the surface, 27 in the 50-meter tow, and 43 in the 100-meter tow. Thirty- one species (54 per cent) were each confined to a single tow and only 3 were found in all three tows. Corycaeus, Farratmla, and Oncaea appeared in all three tows, but Candacia, Oithona, and Sapphirina were not present at the surface. The disparity ill \ertical distribution is slightly less than at the previous station, but still remains quite large. H.vRBOR OF Apra, Guam May 22, 1929; 14° 00' N, 148° 00' E; 14 species Acrocalanus gracilis 2 Farranula gibbula f rostrata r Labidocera detruncata f Microsetella rosea 1 Neocalanus tenuicornis 2 Oithona attenuata 1 similis ' 2 Oncaea minuta r venusta 2 Paracalanus parvus a Temora discaudata 1 Undinula darwinii f vulgaris a Although this surface tow was made in the harbor, the copepods here do not differ at all from those in the open ocean. Evidently such littoral forms as ma>' live around the coasts of these islands do not venture far from shore. 126 COPEPODS OF LAST CRUISE OF CARNEGIE Station 109 May 29, 1929; 23° 22' N, 144° 08' E; bottom depth, 5252 m; 90 species Depth of tow, m Temperature, °C SaUnity, o/oo N'olume of tow, cm' 50 100 Depth of tow, m 50 100 27.4 23.1 19.4 Density (o-tp) 22.6 24.1 25.2 35.0 U.9 34.8 Hvdrogen-ion cone. (pH) 8.23 8.23 8.22 32 64 128 Length of tow, miles 1.4 1.5 1.5 Acartia danae . . c a Acrocalanus gibber f . . 5 graciUs f f c longicornis r f Aetideus armatus . . . . 3 Calanus minor . . f f Calocalanus pavo . . 4 f plumulosus . . 2 3 styliremis . . . . 2 Candacia bispinosa . . f 2 simplex . . f f truncata . . c f varicans . . 2 Canthocalanus pauper . . . . 4 Centropages calaninus 2 2 elongatus . . 2 Clausocalanus arcuicornis 2 f c furcatus . . r Clytemnestra scutellata . . . . 4 Copilia denticulata . . f mirabilis . . 3 quadrata 2 f recta . . 4 5 vitrea . . . . 2 Corycaeus agilis . . r crassiusculus f a c dubius . . r flaccus 1 lautus r longistyHs . . . . f pumilus r speciosus . . c c typicus . . r Euaetideus giesbrechti 1 Eucalanus attenuatus . . f f elongatus . . 2 Euchaeta acuta . . 2 marina . . a f Euchirella brevis 2 1 Farranula carinata a c gibbula c gracilis f rostrata a f f Haloptilus longicornis . . . . f Heterorhabdus papilliger . . . . f Heterorhabdus spinifrons Labidocera detruncata Lubbockia squillimana Lucicutia clausii flavicornis longicornis Macrosetella gracilis oculata Mecynocera clausi Microcalanus pusillus pygmaeus Microsetella rosea Monstrilla inserta Neocalanus gracilis robustior tenuicornis Oithona attenuata plumifera similis spinirostris Oithonina nana Oncaea conifera curta media minuta similis tenella venusta Onchocalanus nudipes, n. sp. Paracalanus parvus pygmaeus Phaenna spinifera Pleuromamma abdominalis. . Pontella lobiancoi Pontellina plumata Pseudocalanus minutus Sapphirina angusta auronitens metallina nigromaculata stellata Scolecithricella bradyi Scolecithrix danae Undinula caroli darwinii 2cr f f 29 a f f 2 f f 3 r The high surface temperature fell 4° at the 50-meter depth and 4° more at the 100-meter depth; the salinity and hydro- gen-ion concentration remained almost constant. There were 20 species in the surface tow, 57 in the 50-meter tow, and 57 in the 100-meter tow. Fifty-three species (60 per cent) were each confined to a single depth and 7 were present at all three depths. The length of the three tows was almost exacth' the same, but the 100-meter tow had twice the volume of the 50-meter tow and four times that of the surface tow. Corycaeus, Farranula. and Oncaea were distributed at all three depths; Candacia, Eucalanus, Euchaeta, and Oithona did not appear in the surface tow. A solitary specimen of one of the 5 Sapphirina species appeared at the surface, but all the others were confined to the deeper tows. The 50-meter LISTS OF SPECIES BY STATIONS tow contains one of the two records of Monstrilla inscrta for the entire cruise, 2 females. Two young males of a Pontella species (probably lobiancoi), whose fifth legs were not fully developed, were captured in the surface tow. Again the small 127 number of both species and specimens (except those of Far- ranida) found at the surface indicates that a strong down- ward migration of the copepods had been in progress before the towing. Station 110 May 31, 1929; 26° 20' N, 144° 24' E; bottom depth, 3036 m; 55 species Depth of tow, m Temperature, °C Salinit>', 0/00 \'olunie ol tow, cm' SO 100 Depth of tow, m ,S0 100 23.8 18.3 17.9 Density (ctip) 23.4 2.S.i 25.5 34.7 34.7 34.7 Hvdrogen-ion cone. (pH ) 8.18 8,18 8.14 48 48 48 Length of tow, miles 0.5 0.5 0.5 Acartia danae Acrocalanus gracilis Aetideus armatus Calanus minor propinquus Candacia bispinosa simplex Canthocalanus pauper. . . . Clausocalanus arcuicornis . furcatus Clytemnestra scutellata. . . Copilia mirabilis Corycaeus catus crassiusculus limbatus pacificus pumilus typicus Eucalanus attenuatus Euchaeta marina Karranula carinata gibbula rostrata Haloptilus ornatus, juv. . . Heterorhabdus papilliger. . spinifrons Labidocera detruncata. . . Lubbockia squillimana. . . , Icf f 9 Lucicutia clausii flavicornis Macrosetella gracilis Mecynocera clausi Megacalanus longicornis Microcalanus pygmaeus Neocalanus gracilis robustior tenuicornis Oithona similis spinirostris Oncaea conifera media f minuta notopa venusta f Pandarus satyrus on a ; Paracalanus aculeatus parvus f pygmaeus Phaenna spinifera Pseudocalanus minutus Rhincalanus cornutus Sapphirina angusta Scolecithricella bradyi Scolecithrix danae Undinula darwinii hark The moderate surface temperature fell 6° in the 100 meters, the salinity and hydrogen-ion concentration remain- ing practically the same. There were 14 species in the surface tow, 32 in the 50-meter tow, and ii in the 100-meter tow. Thirty-three species (60 per cent) were each confined to a single depth and 6 were present at all three depths. Corycaeus, Oithona. and Oncaea were distributed at all three depths, but the 3 Farranida species were confined to the surface tow. Candacia and Sapphirina appeared only in the 50-meter tow. Fifteen specimens of Pandarus satyrus. including both sexes, were taken from a shark captured at the surface and con- stitute the onl\- record for this parasitic copepod. BetWEEX stations 110 AND HI June 2, 1929; 30° 08' \, 143° 56' E; 6 species Acartia danae a Acrocalanus gracilis a Corycaeus crassiusculus 3 longistylis 1 Labidocera detruncata 1 Pleuromamma gracilis 2 This surface tow yielded onl\- 7 specimens besides Acartia and Acrocalanus. both of which were quite abundant. 128 COPEPODS OF LAST CRUISE OF CARNEGIE Station 111 June 3, 1929; 31° 00' N, 144° 16' E; bottom depth, 6008 m; 37 species Depth of tow, m Temperature, °C Salinity, o/oo X'olume of tow, cm' 50 100 Depth of tow, m 50 100 19.3 18.1 Density (o-tp) 24.8 25.5 34.5 34.7 Hvdroijen-ion concentration (pH) 8,18 8.13 32 32 Length of tow, miles 1.8 1.9 Acartia danae Acrocalanus gibber gracilis Calanus minor Calocalanus plumulosus. . . Candacia curta simple.x Canthocalanus pauper. . . . Clausocalanus arcuicornis. Clytemnestra scutellata. . . Corycaeus crassiusculus. . . flaccus longistylis ovalis pumilus speciosus typicus Eucalanus elongatus Euchaeta acuta Euchaeta marina . . 1 Heterorhabdus papilliger . . 2 Lucicutia clausii . . f Mecynocera clausi 3 5 Microcalanus pusillus . . 1 pygmaeus 2 Neocalanus gracilis 1 f tcnuicornis . . 1 Oithona similis c f Oncaea media f minuta f f similis 2 venusta c c Paracalanus parvus c c pygmaeus . . 3 Pseudocalanus minutus c c Scolecithricella bradyi . . 2 Undinula darwinii f f The temperature and hydrogen-ion concentration dimin- ished a little at the 100-meter depth, and the salinity in- creased. There were 24 species in the 50-meter tow and 25 in the 100-meter tow. Twenty-five species (70 per cent) each appeared at a single depth and 12 at both depths. Corycaeus and Oncaea were more numerous in the 50-meter tow; Farran- ula did not appear in either tow. Probably Farranula would have been present in the lost surface tow as at station 110. LISTS OF SPECIES BY STATIONS 129 Station 112 June 5, 1929; 3i° 51' N, 141° 15' E; bottom depth, 3931 m; 85 species Depth of tow, in Temperature, °C Salinity, 0/00 \'olume of tow, cm' 50 100 Depth of tow, m 50 100 23.2 21.7 19.8 Density (fftp) 23,5 24.2 25.0 34.6 34.6 34.7 Hydrogen-ion cone. (pH) 8.22 8.22 8.20 96 80 80 Length of tow, miles 2.7 2.4 2.0 Acartia danae Acrocalanus gibber gracilis longicornis Aetideus arniatus Calanus minor propinquus Calocalanus pavo plumulosus styliremis Candacia aethiopica bipinnata bispinosa curta norvegica simplex truncata Canthocalanus pauper Centropages calaninus Clausocalanus arcuicornis furcatus Clytemnestra scutellata Copilia denticulata mirabilis recta Corycaeus crassiusculus furcifer lubbockii pumilus speciosus typicus Danodes plumata, n. gen. and n. sp. Eucalanus attenuatus crassus elongatus Euchaeta acuta marina Farranula carinata concinna gibbula rostrata Heterorhabdus papilliger Labidocera detruncata 2 2 c 2 1 f 39 Lucicutia clausii flavicornis Macrosetella gracilis oculata Mecynocera clausi Megacalanus longicornis. Microcalanus pusilkis. . . . [lygmaeus Microsetella rosea Miracia efferata Monstrilla inserta Neocalanus gracilis robustior tenuicornis Oithona attenuata plumifera similis spinirostris Oncaea curta media minuta similis tenella venusta Paracalanus aculeatus. . , parvus Pleuromamma gracilis. . Pontellina plumata Pseudocalanus minutus. Rhincalanus cornutus . . nasutus Sapphirina angusta auronitens nigromaculata opalina Scolecithricella bradyi. . Scolecithri.x danae Temora discaudata Undeuchaeta plumosa . . Undinula caroli darwinii vulgaris 2 2 a 3 2 5 r 1 59 f f 2 f f c f 2 The moderate surface temperature fell 3?5 in 100 meters, the salinity and hydrogen-ion concentration remaining nearly constant. There were 41 species in the surface tow-, 57 in the 50-meter tow, and 41 in the 100-meter tow. Forty-two species (50 per cent) were each confined to a single tow and 15 were present in all three tows. Corycaeus, Farranula. and Oncaea were well distributed in all three tows, but Oithona did not appear in the surface tow and Candacia was confined to the 50-meter tow with one exception. The 50-meter tow contains the second of two records for Monstrilla inserta, 5 females. I30 COPEPODS OF LAST CRUISE OF CARNEGIE Station 1 13 June 25, 1929; 34° 44' N, 141° 04' E; bottom depth, 2911 m; 93 species Depth of tow, m Temperature, °C Sahnity, o/oo X'olume of tow, cm' 50 100 Depth of tow, m 50 100 24.1 23.7 21.5 Density (trtp) 23.2 23.6 24.5 34. S 34.5 34.6 Hydrogen-ion cone. (pH) 8.25 8.25 8.23 32 64 128 Length of tow, miles 1.7 1.6 1.7 Acartia danae negUgens 3 Acrocalanus gibber c gracihs a longicornis f monachus Aetideus armatus Anomalocera patersonii Calanus minor propinquus Calocalanus pavo plumulosus styhremis Candacia bipinnata bispinosa curta longimana norvegica pachydactyla simplex truncata Canthocalanus pauper Centropages calaninus 2 Clausocalanus arcuicornis c Copilia denticulata mirabilis recta Corycaeus catus r crassiusculu.s c dubius 3 lautus longistyHs robustus speciosus typicus Euaetideus giesbrechti Eucalanus attenuatus crassus elongatus Euchaeta acuta marina Farranula carinata curta gibbula rostrata Haloptilus longicornis ornatus Haloptilus spiniceps Heterorhabdus papilliger. Labidocera detruncata. . . Lubbockia aculeata squillimana Lucicutia clausii flavicornis Macrosetella gracilis oculata Mecynocera clausi Megacalanus longicornis. Microcalanus pusillus. . . . pygmaeus Microsetella norvegica. . . rosea Miracia efferata Neocalanus gracilis robustior tenuicornis Oithona attenuata plumifera similis spinirostris Oncaea conifera media mediterranea minuta notopa similis tenella venusta Pachos tuberosum Pachyptilus abbreviatus. Paracalanus parvus pygmaeus Pseudocalanus minutus. . Rhincalanus cornutus. . . . nasutus Sapphirina angusta auronitens metallina Scolecithricella bradyi . . . Scolecithrix danae Undinula caroli darwinii vulgaris c f 2 1 c 4 f 2 a 19 f 2 f 1 1 r f 2 The moderate surface temperature fell 2?5 in the 100 meters, the salinit},- and hydrogen-ion concentration remain- ing nearly constant. T\vent\-fi\e species appeared in the surface tow, 56 in the 50-meter tow, and 60 in the 100-meter tow. Eifty-five species (60 per cent) were each confined to a single tow and 12 were present in all three tows. Corycaeus, Farranula, and Oncaea were distributed at all three depths, but Candacia (except simplex) and Oithona did not appear in the surface tow, and Sapphirina did not appear in the 100- meter tow. The three tows were ail of about the same length. LISTS OF SPECIES BY STATIONS 131 but the volume of the 100-meter tow was four times that of the surface tow and twice that of the 50-meter tow. The three genera Candacia, Corycaens, and Oncaea each present 8 species and when combined constitute more than a ciuarter of the species total for the station. Again there is good evidence that the reaction to light within a copepod genus is specific rather than generic. Two of the 8 species of Cory- caeus were confined to the surface tow, 2 to the 50-meter tow, and 2 to the 100-meter tow, a seventh was equally distributed in two tows, and the eighth in all three tows. Station 114 June 27, 1929; 36° 38' N, 143° 34' E; bottom depth, 6630 m; 66 species Depth of tow, m Temperature, °C Salinity, o '00 X'olume of tow, cm' 50 100 Depth of tow, m 50 100 19.9 16.2 13.0 Density (fftp) 24.2 25.6 26.4 34.3 34.5 34.4 Hydrogen-ion cone. (pHj 8.15 8.08 8.00 32 80 48 Length of tow, miles 0.8 0.8 0.8 Acartia danae Acrocalanus gibber gracilis Aetideus armatus Calanus helgolandicus . . . . minor propinquus Candacia armata bipinnata simple.K varicans Clausocalanus arcuicornis. Corycaeus cat us crassiusculus furcifer pumilus speciosus Eucalanus attenuatus crassus elongatus Euchaeta acuta marina Euchirella curticauda intermedia Farranula carinata gibbula rostrata Haloptilus acutifrons Heterorhabdus papilligcr, . spinifrons Labidocera detruncata. . . . Lubbockia aculeata Lucicutia clausii Lucicutia flavicornis Megacalanus longicornis. . princeps Microcalanus pusillus pygmaeus Microsetella rosea Miracia efferata Neocalanus gracilis robustior tenuicornis Oithona attenuata plumifera similis spinirostris Oncaea conifera curvata media mediterranea minuta tenella x'enusta Paracalanus parvus pygmaeus Pleuromamma gracilis. . . . Pseudocalanus minutus. . . Rhincalanus nasutus Sapphirina nigromaculata . stellata Scolecithricella bradyi , . . . marginata Scolecithrix danae Temora discaudata Undinula darwinii The temperature was low at the surface and fell 7° in the 100 meters, but the salinit>' and h\drogen-ion concentration varied little. Thirteen species were taken in the surface tow, 35 in the 50-meter tow. and 45 in the 100-meter tow. Fort\- four species (67 per cent) were each confined to a single depth and only 5 appeared at all three depths. Corycaeus was found in all three tows, but Farranula was not present in the 50-nieter tow and Eucalanus, Euchaeta, Oithona, and Oncaea were not present at the surface, the 7 species of the latter, with one e.xception, being confined to the 100-meter tow. The three tows were of exactly the same length but differed considerabK' in volume, that of the surface • tow being the smallest and of the 50-meter tow the largest. The unequal \ertical distribution again bears witness to a strong downward migration on the part of a large proportion of the species. 132 COPEPODS OF LAST CRUISE OF CARNEGIE Station 1 15 June 29, 1929; 37° 40' N, 145° 26' E; bottom depth, 5396 m; 36 species Depth of tow, m Temperature, °C Salinity, o/oo X'olume of tow, cm' 50 100 Depth of tow, m 50 100 20.5 17.5 15.6 Density (drogen-ion concentration changed but little. Onl>- 4 species were taken at the surface, 24 in the 50-meter tow, and 18 in the 100-meter tow. Twenty- three species (70 per cent) were each confined to a single tow tows. Corycaeus, reduced to a single species, and Oithona and Oncaea with 3 species each, did not appear in the surface tow. Candida simplex was here confined to the 100-meter tow, though usually found nearer the surface. The 50-meter tow was slightly shorter than either of the others but had the and only 1 {Paracalanus parvus) was present in all three largest volume. 134 COPEPODS OF LAST CRUISE OF CARNEGIE Station 117 July 3, 1929; 40° 20' N, 150° 58' E; bottom depth, 5296 m; 33 species Depth of tow, m Temperature, °C Salinity, o/oo \'olume of tow, cm' SO 100 Depth of tow, m SO 100 15.9 12.5 8.8 Density (trtp) 25.2 26.1 26.0 34.3 34.2 34.0 Hydrogen-ion cone. (pH) 8.17 8.06 7.98 384 128 96 Length of tow. miles 0.9 0.8 0.9 Acartia negligens Acrocalanus gracilis Calanus minor propinquus Calocalanus pavo plumulosus Candacia varicans Canthocalanus pauper. . . . Clausocalanus arcuicornis. Corycaeus crassiusculus. . . pumilus typicus Eucalanus attenuatus elongatus subtenuis Farranula gibbula rostrata Heterorhabdus papilliger. Lucicutia clausii flavicornis Metridia lucens Microsetella rosea Neocalanus tenuicornis. . . Oithona similis spinirostris Oncaea minuta venusta Paracalanus parvus pygmaeus Pseudocalanus minutus. . Sapphirina auronitens. . . . stellata Scolecithricella porrecta . . The surface temperature was low and fell almost 50 per the 100-meter tow. Twenty-four species (75 per cent) were cent in the 100 meters; the salinit>- and hydrogen-ion con- each present in a single tow and 2 in all three tows. Cory- centration changed comparatively little. Six species were caeus, Eucalanus, and Oncaea appeared in the two deeper taken in the surface tow, 16 in the 50-meter tow, and 22 in tows, Farranula only at the surface, and Oithona in all tows. LISTS OF SPECIES BY STATIONS 135 Station 118 July 5, 1929; 42° 29' N, 155° 24' E; bottom depth, 5404 m; 24 species Depth of tow, m Temperature, °C SaHnity, 0/00 \olume of tow, cm' 50 100 Depth of tow, m 10.1 8.1 6.1 Density (o-tp) ,?3 . 8 .?,< . 7 ,S3 . 7 Hydrogen-ion cone. (pH) 96 \<)2 140 Length of tow, miles 25.8 8.21 1.4 50 26.5 8.21 1.3 100 27.0 7.94 1.4 Acrocalanus gracilis Bathycalanus rigidus Calanus finmarchicus hyperboreus Calocalanus pavo Clausocalanus arcuicornis. Clytemnestra rostrata. . . . Eucalanus attenuatus crassus elongatus Euchirella brevis Lucicutia clausii Lucicutia flavicornis. . . . Macrosetella gracilis. . . . Metridia longa lucens M icrosetella rosea Oithona attenuata setiger similis spinirostris Oncaea minuta Paracalanus parvus Pseudocalanus minutus. The surface temperature was 5° lower than at the pre- ceding station and fell 4° in the 100 meters; the salinity remained practically the same, but the hydrogen-ion con- centration diminished at the 100-meter level. Calanus finmarchicus was the only species found in the surface tow; 13 species were found in the 50-meter tow, and 21 in the 100-meter tow. Thirteen species (54 per cent) were each con- fined to a single depth and no species was found at all three depths. The numbers of both species and individuals are so small as to make it evident that the bulk of these northern tows is made up of other constituents of the plankton. The two deeper tows contain the only record for Bathycalanus rigidus. Corycaeus and Farranula entirely disappear and do not reappear until at station 130, and Oncaea is reduced to a single species. Oithona yielded 4 species but none of them were in the surface tow. Depth of tow, m Temperature, °C Salinity, 0/00 X'olunie of tow, cm' .Station 119 July 7, 1929; 45° 24' N, 159° 36' E; bottom depth, 5198 m; 16 species 50 100 Depth of tow, m 6.9 3.0 1.6 Density (o-,p I 25.8 32.9 33.0 ii.I Hydrogen-ion cone. (pH) 7.96 31 31 62 Length of tow, miles 1.3 50 26.6 7.92 1.3 100 27 7.85 1.4 Acrocalanus gracilis Calanus cristatus hyperboreus Clausocalanus arcuicornis. Eucalanus elongatus subtenuis Macrosetella gracilis Metridia lucens M icrosetella rosea Neocalanus gracilis robustior Oithona attenuata similis Paracalanus parvus Pseudocalanus minutus. Scolecithricella porrecta. The surface temperature was the lowest for the entire cruise and fell almost 80 per cent in the 100 meters; the salinity was also low and increased slightly, and the h>drogen- ion concentration diminished. Two species were found in the surface tow, 9 in the 50-meter tow, and 14 in the 100-meter tow. Nine species (56 per cent) were each confined to a single tow and 2 were present in all three tows. Although the temperature at the 50-meter le\el was only 3° and at the 100-meter level 1?6 above the freezing point, all the species except 2 had retired to the lower levels. This indicates that even a temperature which is very close to freezing is not an effective deterrent to negative phototropism. Aversion to strong light is more powerful than to low temperature, and the downward migration occurs regardless of temperature. 136 COPEPODS OF LAST CRUISE OF CARNEGIE Depth of tow, m Temperature, °C Salinity, 0/00 X'olume of tow, cm' Station 120 July 9, 1929; 47° 02' N, 166° 20' E; bottom depth, 5874 m; 19 species 50 100 Depth of tow, m 50 100 7.1 2.1 2.0 Densit\- ffftp) 25.8 26.5 27.0 ^2.0 33.0 33 . 2 Hydrogen-ion cone. (pH) 7.98 7.90 7.84 310 186 159 Length of tow, miles 1.2 1.4 1.6 Acrocalanus gracilis Calanus cristatus finmarchicus hyperboreus Clausocalanus arcuicornis. Eucalanus attenuatus elongatus Gaidius tenuispinus Macrosetella gracilis Metridia longa Metridia lucens Microsetella rosea Neocalanus gracilis Oithona similis Oncaea minuta Paracalanus parvus Pseudocalanus minutus. Scolecithricella minor. . . porrecta. •Development stages. The surface temperature was only a trifle higher than at the preceding station, and fell 72 per cent to only 2° above freezing at the two deeper le\els. Six species \vere found at the surface, 13 in the 50-meter tow, and 13 in the 100-meter tow. Nine species (47 per cent) were each confined to a single level and 3 were found at all three levels. Again we find a wholesale migration from the surface to the two lower levels in spite of the decrease in temperature. It will be noted also that 3 of the species were represented at the surface by development stages only. St.\tion 121 July 11, 1929; 46° 05' N, 171° 32' E; bottom depth, 5684 m; 18 species Depth of tow, m Temperature, °C Salinity, 0/00 X'olume of tow, cm' 50 100 Depth of tow, m 50 100 7.4 3.5 2.0 Density (o-tpl 25.7 26.5 27.0 32.9 33 . 33.1 Hydrogen-ion cone. (pH) 7.98 7.92 7.86 288 368 192 Length of tow, miles 1.3 1.3 1.4 Acrocalanus gracilis Calanus finmarchicus hyperboreus Clausocalanus arcuicornis. Eucalanus elongatus Euchaeta acuta Gaidius tenuispinus Metridia longa lucens Microsetella rosea Neocalanus gracilis robustior Oithona similis Oncaea minuta Paracalanus parvus Pseudocalanus minutus. Scolecithricella bradyi . . porrecta 'Development stages. The surface temperature was still very low and fell 73 per cent in the 100 meters; the salinity was also low and increased a trifle, and the hydrogen-ion concentration dimin- ished. Only 2 species were found at the surface, 1 of which was made up of development stages; II species were found species (44 per cent) were each confined to a single tow and only 1 was present in all three tows. Oithona and Oncaea were each reduced to a single species; the former was abun- dant in all three tows, the latter appeared onl>' in the 100- meter tow. Although the copepods were comparatively few, in the SO-meter tow and 16 in the 100-meter tow. Eight the volumes of the three tows were each quite large. LISTS OF SPECIES BY STATIONS 137 Station 122 July 13, 1929; 46° 16' N, 174° 03' E; bottom depth, 6077 m; 21 species Depth of tow, ni Temperature, °C Salinity, 0/00 X'olume of tow, cm' 50 100 Depth of tow, m 50 100 8.2 3.6 2.4 Density (uip) 25.5 26.5 26.9 S2.8 33.0 33 . 1 Hydrogen-ion cone. (pH) T.yg 7.94 7.90 160 256 256 Length of tow, miles 1.3 2.0 2.1 Acrocalaniis gracilis Calanus cristatus finmarchicus hyperborcus Clausocalanus arcuicornis. Eucalanus attenuatus elongatus Euchaeta acuta . . . : Gaidius tcnuispinus Metridia longa lucens Microsetella rosea Neocalanus gracilis robustior Oithona similis Oncaea minuta Paracalanus parvus pygmaeus Pscudocalanus minutus. Scolecithricella bradyi . . porrecta The surface temperature was a little higher but fell 70 per meter tow. Nine species (45 per cent) were each confined to cent in the 100 meters; both the salinit)- and the hydrogen- ion concentration were low, the former increasing slightly with depth, the latter decreasing. Five species were found at the surface, 11 in the 50-meter tow, and 19 in the 100- a single tow and 2 were present in all three tows. Oithona and Oncaea were still represented by a single species each, the former abundant in all three tows. The surface tow was made up almost entirely of Oithona and Calanus finmarchicus. St.^tion 123 July 15, 1929; 50° 27' N, 172° 51' \V; bottom depth, 5464 m; 16 species Depth of tow, m Temperature, °C Salinity, 0/00 \ olume of tow, cm' 50 100 Depth of tow, m 50 100 8.1 4.4 3.0 Density (fftp) 25.5 26,3 27.1 32.7 32.8 M . 3 Hydrogen-ion cone. (pH) 8.03 7.94 7.79 320 Length of tow, miles 0.8 1.0 1.0 Acartia danae negligens Acrocalanus gracilis Calanus finmarchicus hyperborcus Clausocalanus arcuicornis. Eucalanus elongatus Megacalanus princeps Metridia lucens Microsetella rosea Neocalanus robustior. . . Oithona similis Oncaea minuta Paracalanus parvus Pseudocalanus minutus. Scolecithricella porrecta. 'Development stages. The surface temperature was still low, and fell 5° in the 100 meters; the salinity increased slightly and the hydrogen- ion concentration diminished. Five species were found at the surface, 9 in the 50-meter tow, and 13 in the 100-meter tow. Seven species (40 per cent) w'ere each confined to a single tow and 2 were present in all tows. The 2 Calanus species were represented at the surface by development stages. No Oithona, Oncaea, or Metridia appeared at the surface. 138 COPEPODS OF LAST CRUISE OF CARNEGIE Station 124 July 17, 1929; 52° 19' N, 162° 02' \V; bottom depth, 4780 m; 17 species Depth of tow, m Temperature, °C Salinity, o/oo Volume of tow, cm' 50 100 Depth of tow, m 50 100 q.,? 5.3 4.0 Density (fftp) 25.2 26.1 27.2 32.6 32.7 33.6 Hydrogen-ion cone. (pH) 8.04 8.02 7.64 31 256 93 Length of tow, miles 1.2 1.4 1.5 Acartia danae negligens Acrocalanus gracilis Calanus cristatus finmarchicus hyperboreus Clausocalanus arcuicornis. Eucalanus attenuatus elongatus Megacalanus longicornis . Metridia lucens Neocalanus gracilis Oithona similis Oncaea minuta Paracalanus parvus Pseudocalanus minutus. . Scolecithricella porrecta. The surface temperature was a little higher but dropped 5° in the 100 meters; the salinity was low and increased slightly with depth, and the hydrogen-ion concentration diminished. Nine species were taken at the surface, 10 in the 50-meter tow, and 13 in the 100-meter tow. Only 4 species (25 per cent) were each confined to a single tow, and 2 were present in all three tows. The surface tow contained many development stages along with the adults, but the former were so young they could not be identified with any certainty. The 50-meter tow was composed largely of Euca- lanus, Metridia, and Oithona: Metridia was also \-ery abun- dant in the 100-meter tow, but did not appear at the surface, whereas Oithona was abundant at the surface and in the 50- meter tow. Oncaea was confined to the two deeper tows. Station 125 July 19, 1929; 51° 58' N, 150° 39' W; bottom depth, 4536 m; 10 species Depth of tow, m Temperature, °C Salinity, o/oo X'olume of tow, cm' 50 100 Depth of tow, m 50 100 10.5 5.5 4.2 Density (irtp) 25.1 26.1 26.6 32.7 32.8 32.9 Hydrogen-ion cone. fpH) 8 03 7.98 7.89 31 64 93 Length of tow, miles 1.4 1.0 1.1 Acrocalanus gracilis Calanus finmarchicus hyperboreus Clausocalanus arcuicornis. Eucalanus attenuatus Eucalanus elongatus. . . . Metridia lucens Neocalanus gracilis Oithona similis Pseudocalanus minutus. 'Development stages. The surface temperature was a degree higher than at the were taken in the 50-meter tow, and 7 in the 100-meter tow. preceding station, but fell 6° in the 100 meters. The low salinity increased a trifle, and the h>-drogen-ion concentration diminished. Three species were taken at the surface, 1 of them represented entirely by development stages; 8 species Only 4 species (40 per cent) were each confined to a single tow, and 2 were present in all three tows. Oithona was abun- dant in all three tows, but on the other hand, Oncaea does not appear in any of them. LISTS OF SPECIES BY STATIONS 139 Station 126 July 21, 1929; 48° 05' N, 142° 56' W; bottom depth, 4382 in; 13 species Depth of tow, m Temperature, °C Salinity, 0/00 \ olume of tow, cm^ 50 100 Depth of tow, m 50 100 11.2 7.7 6.4 Density ('-fi\e species (80 per cent) were each confined to a single tow and 5 were present in all three tows. The two deeper tows were 30 per cent longer than the surface tow but the volume of the latter was somewhat larger. Corycaeus, Farranula, and Oncaea re- appear in goodly numbers, the two former well distributed in all three tows, the latter strictly confined to the 100-meter tow. The Undeuchaeta which was recorded in the deepest tow was a juvenile male with its fifth legs only partially developed. LISTS OF SPECIES BY STATIONS 141 Station 132 September 8, 1929; 31° 38' x\, 128° 48' W; bottom depth, 4251 m; 82 species Depth of tow, m Temperature, °C Sahnity, o/uo \'olume of tow, cm' 50 100 21.0 17. .S 14.3 33 . 9 3i . 8 33 . 4 32 48 48 Depth of tow, m Density (trtp) Hydrogen-ion cone. (pH ) Length of tow, miles 50 100 23 . f) 24.7 25.3 8.34 8 . M 8.30 1.0 1.0 1.3 Acartia danae ncgligens Acrocaianiis gibber gracihs Calanus minor Calocalanus pavo plumulosus styliremis Candacia bipinnata norvegica simplex triincata Clausocalanus arcuicornis. furcatus Clytemnestra rostrata . . . . scutellata Corycaeus cat us clausi crassiusculus flaccus lautus limbatus longistylis pumilus robustus speciosus typicus Eucalanus attenuatus elongatus subtenuis Farranula carinata concinna rostrata Haloptilus acutifrons longicornis ornatus plumosus spiniceps Heterorhabdus papilHger. . spinifrons Heterostylites longicornis. Lubbockia aculeata squillimana Lucicutia clausii flavicornis Macrosetella gracilis. . . . Mecynocera clausi Microcalanus pusillus. . . pygmaeus Microsetella norvegica. . rosea Neocalanus gracilis robust ior tenuicornis Oithona brevicornis. , . . similis spinirostris Oithonina nana Oncaea conifera curta media mediterranea minuta notopa similis subtihs tenella venusta Pachos punctatum Paracalanus acultatus. . parvus pygmaeus Phaenna spinifera Pleuromamma gracihs . . Pontellina plumata Pseudocalanus minutus. Sapphirina angusta auronitens metallina Spinocalanus caudatus. . Undinula darwinii \'cttoria granulosa The temperature was moderate at the surface and fell nearly 7° in the 100 meters; the salinity and hydrogen-ion concentration both diminished a little. Thirteen species were taken at the surface, 63 in the 50-meter tow, and 63 in the 100-meter tow. Thirty-two species (40 per cent) were each confined to a single tow and 7 were present in all three tows. Corycaeus was represented by 11 species and Oncaea by 10 species, and 19 of these 21 species appeared only in the two deeper tows. Farranula, however, was distributed in all three tows. There were 5 species of Haloptilus, 2 of Heterorhabdus, and 3 of Oithona; all 10 species were confined to the two deeiier tows. 142 COPEPODS OF LAST CRUISE OF CARNEGIE Station 133 September 10, 1929; 29° 21' N, 132° 30' W; bottom depth, 4426 m; 71 species Depth of tow, m Temperature, °C Salinity, 0/00 Volume of tow, cm' 50 100 Depth of tow, m 50 100 22.6 20.7 18.4 Density (fftp.l 23.8 24.5 25.4 34.7 34.7 34.7 Hydrogen-ion cone, (pH) 8.47 8.37 8.31 32 32 32 Length of tow, miles 1.1 1.1 1.2 Acartia danae Acrocalanus gibber gracilis Calanus minor Calocalanus pavo Candacia bispinosa simplex Centropages calaninus. . . . hamatus Clausocalanus arcuicornis. furcatus Clytenmestra rostrata. . . . scutellata Corycaeus crassiusculus. . . fiaccus lautus limbatus longistylis pumilus robustus speciosus typicus Eucalanus crassus elongatus Euchaeta marina Euchirella brevis curticauda Farranula carinata curta gibbula rostrata Haloptilus longicornis. ... spiniceps Heterorhabdus spinifrons. Labidocera detruncata. . . Lubbockia aculeata Lubbockia squillimana. . . Lucicutia clausii flavicornis Macrosetella gracilis Mecynocera clausi Megacalanus longicornis. Microcalanus pusillus. . . . Microsetella norvegica. . . rosea Neocalanus gracilis robustior tenuicornis Oithona attenuata brevicornis similis spinirostris Oithonina nana Oncaea curta media mediterranea minuta venusta Paracalanus aculeatus. . . parvus pygmaeus Pontella atlantica lobiancoi Pontellina plumata Pseudocalanus minutus. Sapphirina auronitens. . . metalHna opalina Scolecithrix danae Undeuchaeta major. . . . Undinula darwinii The temperature dropped only 4° in the 100 meters; the salinity and hydrogen-ion concentration remained almost constant. Fourteen species were taken at the surface, 53 in the 50-meter tow, and 3i in the 100-meter tow. Forty-seven species (66 per cent) were each confined to a single tow and 6 were found in ail three tows. Corycaeus, Farranula, Oithona, and Oncaea were for the most part in the 50-meter tow, and Oncaea did not appear at all in the surface tow. The 100- meter tow contains one of the two records for Centropages hamatus in the Pacific; since in the other record, station 55, it was found at the surface, very little can be told about its reaction to light. LISTS OF SPECIES BY STATIONS M3 Station 134 September 12, 1929; 27° 45' N, 135° 22' \V; bottom depth, 4528 m; 46 species Depth of tow, m Temperature, °C Salinity, o/oo \olume of tow, cm' 50 100 Depth of tow, m 50 100 22.8 19.7 18.1 Density (' and hydrogen-ion concentra- tion remained almost unchanged. Eighteen species were taken at the surface, 28 in the SO-meter tow, and 34 in the 100-meter tow. Twenty-four species (52 per cent) were each confined to a single tow and 11 were present in all three tows. Candacia. Corycaeus, Farranula, Oithona, and Oncaea were each distributed in all three tows, an exceptional record for Candacia. The three tows were of exactly the same length, but the volume of the surface tow was one-half larger than that of the 50-meter tow and three times that of the 100-meter tow. 150 COPEPODS OF LAST CRUISE OF CARNEGIE Station 141 October 5, 1929; 29° 02' N, 161° 11' W; bottom depth, 5667 m; 56 species Depth of tow, m Temperature, °C Sahnity, o/oo \'olume of tow, cm^ 50 Depth of tow, m 50 25.8 24.7 Density (trtp) 23.2 23.8 35.1 35.2 Hydrogen-ion concentration (pH) 8.34 8.34 32 48 Length of tow, miles 2.4 2.1 Acartia danae Acrocalanus gibber graciHs longicornis Calanus minor Calocalanus pavo styHremis Candacia bispinosa simplex Centropages calaninus . . . . Clausocalanus arcuicornis. furcatus Clytemnestra scutellata. . . Copilia denticulata quadrata Corycaeus crassiusculus. . . lautus longistylis pumilus speciosus Eucalanus attenuatus Euchaeta acuta marina Euchirella curticauda Farranula carinata gibbula rostrata Labidocera detruncata. . . . Macrosetella gracilis oculata Mecynocera clausi Megacalanus longicornis. Microcalanus pusillus. . . . Microsetella rosea Miracia efferata Neocalanus gracilis robustior tenuicornis Oithona attenuata plumifera similis Oithonina nana Oncaea media minuta notopa venusta Paracalanus aculeatus. . . parvus pygmaeus Pareuchaeta tonsa Pontella tenuiremis Pseudocalanus minutus. . Sapphirina auronitens. . . . nigromaculata Scolecithrix danae Undinula darwinii a 1 c f 19 The temperature was high at the surface and dropped 1° at the 50-meter level; the salinit)- and hydrogen-ion con- centration were practically the same at both depths. Twenty- seven species were taken at the surface and 40 in the 50- meter tow. Forty-fi\e species (80 per cent) each appeared in one tow and not in the other, and 11 were present in both tows. Although shorter than the surface tow, the 50-meter tow had a volume 50 per cent larger. Corycaeus, Farranula, Oithona, and Oncaea each appeared in both tows, but Can- dacia and Euchaeta were not present in the surface tow. Farranula carinata was especiall)' abundant in the surface tow. LISTS OF SPECIES BY STATIONS 151 Station 142 October 7, 1929; 32° 42' N, 160° 44' W; bottom depth, 5787 m; 58 species Depth of tow, m Temperature, °C Salinity, 0/00 \"olume of tow, cm' 50 100 Depth of tow, m 50 100 24.0 21.8 16.5 Density ((7tp) 23 . 5 24.3 25.6 34.8 34.7 34.4 Hydrogen-ion cone. fpH) 8.33 8.30 8.27 48 32 48 Length of tow, miles 0.8 0.8 0.8 Acartia danae Acrocalanus gracilis f longicornis 2 Calanus minor 2 Calocalanus pavo styliremis Candacia aethiopica simplex Canthocalanus pauper Centropages calaninus Clausocalanus arcuicornis furcatus ("lytemnestra rostrata scutellata Corycaeus catus crassiusculus limbatus longistylis robustus speciosus typicus Eucalanus attenuatus Euchaeta marina Farranula carinata a gibbula f rostrata Haloptilus acutifrons longicornis Labidocera acutifrons 2 Labidocera detruncata. . Lubbockia aculeata squillimana Lucicutia clausii Macrosetella gracilis. . . . oculata Mecynocera clausi Microcalanus pusillus. . . pygmaeus M icrosetella rosea Neocalanus gracilis robustior tenuicornis Oithona plumifera similis Oncaea curta media minuta venusta Pachos punctatum Paracalanus parvus pygmaeus Pontellina plumata Pseudocalanus minutus. Sapphirina auronitens. . metallina Scolecithri.x danae Undinula darwinii \ ettoria granulosa The temperature was high at the surface and dropped 7?S in the 100 meters; the salinity and hydrogen-ion concentra- tion both diminished slightly. Sixteen species were found at the surface, 26 in the 50-meter tow, and 47 in the 100-meter tow. Thirty-six species (62 per cent) were each confined to a single tow and 8 were present in all three tows. Farranula was found at all three depths, but onlj- a single species each of Corycaeus and Oncaea and none of Oithona was present in the surface tow. Labidocera detruncata was especially abundant at the surface, adults as well as many development stages. The presence of this species in all three tows is worthy of note as it is usually confined to the surface. 152 COPEPODS OF LAST CRUISE OF CARNEGIE Station 143 October 9, 1929; 34° 06' N, 157° 09' W; bottom depth, 5841 m; 33 species Depth of tow, m Temperature, °C Salinity, o/oo \'olunie of tow, cm' 50 100 22.4 1<).0 13.8 34.3 34.2 34.1 32 32 32 f f 1 2 f a a Depth of tow, m Density () 22.5 25.0 26.6 34.0 34.4 54.0 Hvdrogen-ion cone. (pH) 64 80 32 Length of tow, miles 1.1 0.8 o.y Acrocalanus gibber a gracilis a longicornis c Aetideus armatus Calanus minor Calocalanus pavo r Candacia simplex Canthocalanus pauper f Carnegiella gracihs, n. gen. and n. sp. Centropages calaninus a elongatus violaceus Clausocalanus arcuicornis a furcatus a Clytemncstra rostrata scutellata Copilia denticulata r quadrata Corycaeus crassiusculus f flaccus 2 pumilus speciosus a typicus Eucalanus attenuatus elongatus monachus mucronatus Euchaeta acuta marina f Euchirella brevis Farranula carinata a gibbula f rostrata f Haloptilus longicornis Heterorhabdus papilliger spinifrons 19 Labidocera detruncata. . Lubbockia aculeata squillimana Lucicutia clausii flavicornis longicornis Macrosetella gracilis. . . . oculata Mecynocera clausi Metridia brevicauda . . . Microcalanus pusillus. . . pygmaeus Microsetella norvegica. . rosea Neocalanus tenuicornis. Oithona plumifera similis spinirostris Oithonina nana Oncaea media minuta notopa venusta Paracalanus aculeatus. . parvus pygmaeus Phaenna spinifera Pleuromamma robusta. . Pontella tenuiremis Pontellina plumata Pseudocalanus minutus. Sapphirina angusta auronitens metallina nigromaculata Undinula vulgaris The temperature was high at the surface and fell 13° in 100 meters; the density increased slightly. Thirty species were taken at the surface, 51 in the 50-meter tow, and 45 in the 100-meter tow. Thirty-one species (43 per cent) were each confined to a single depth and 12 were found at all three depths. The 50-meter tow was shortest but yielded the largest volume. Corycaeus, Farranula, and Oncaea appeared in all three tows, but Oithona was absent from the surface. i6o COPEPODS OF LAST CRUISE OF CARNEGIE Station 152 October 27, 1929; 10° 05' N, 139° 44' W; bottom depth, 4830 m; 82 species Depth of tow, m Temperature, °C Salinity, jo/oo \ olume of tow, cm' 50 100 Depth of tow, m 50 100 27.4 14.1 11.3 Density (fftp) 21.6 26.0 26.9 33.6 34.5 34.7 Hvdrogen-ion cone. (pH) 8.35 7.87 7.76 32 32 80 Length of tow, miles 0.1 0.1 0.1 Acartia danae negligens r Acrocalanus gibber gracilis a longicornis f monachus Aetideus armatus Calanus propinquus Calocalanus pavo plumulosus styliremis Candacia simplex Canthocalanus pauper Centropages calaninus elongatus furcatus Clausocalanus arcuicornis furcatus Clytemnestra rostrata scutellata Copilia denticulata vitrea Corycaeus anglicus r crassiusculus r dubius 2 lautus longistylis pacificus speciosus c typicus r Danodes plumata, n. gen. and n. sp. Eucalanus attenuatus elongatus monachus Euchaeta marina Euchirella pulchra Farranula carinata gibbula rostrata Gaetanus miles Gaidius tenuispinus 2 a 19 f f Haloptilus longicornis plumosus Heterorhabdus papilliger. . . spinifrons Labidocera detruncata Lucicutia clausii flavicornis longicornis Macrosetella gracilis Mecynocera clausi Microcalanus pygmaeus. . . . Microsetella rosea Miracia elTerata Neocalanus gracilis tenuicornis Oithona plumifera similis spinirostris Oithonina nana Oncaea media minuta notopa venusta Paracalanus aculeatus parvus Pleuromamma abdominalis. robusta Pontella securifer Pseudocalanus minutus. . . . Rhincalanus cornutus nasutus Sapphirina metallina nigromaculata Scolecithricella abyssalis. . . marginata Scolecithrix danae Spinocalanus magnus Temoropia mayumbaensis. . Undinula caroli darwinii vulgaris The temperature was high at the surface and fell 16° in the 100 meters; the salinity increased and the hydrogen-ion concentration decreased somewhat. Twenty-one species were taken at the surface, 38 in the SO-meter tow, and 56 in the 100-meter tow. Fifty-four species (66 per cent) were each confined to a single depth and 5 were present at all three depths. The three tows were of exactly the same length, but the volume of the 100-meter tow was two and a half times as large as that of either of the others. Corycaeus and Oncaea were present in each of the tows, but neither did Farranula appear in the 50-meter tow nor Oithona in the surface tow. The 100-meter tow contained Temoropia mayumbaensis, which was found also at station 35 in the eastern Pacific. LISTS OF SPECIES BY STATIONS i6i Station 153 October 29, 1929; 7° 45' N, 141° 24' \V; bottom depth, 5003 m; 66 species Depth of tow, m Temperature, °C SaHnity, o/oo X'olunie of tow, cm' 50 100 Depth of tow, m 28.0 28.0 20.5 Density (o-tp) 34.2 34.4 34.7 Hydrogen-ion cone, (pll) 32 32 64 Length of tow, miles 21,7 8.47 1.0 50 22.1 8 . 39 1,7 100 24,8 8.28 1.8 Acartia danae r longiremis Acrocalanus gracilis a Aetideus armatus Calanus helgolandicus minor Calocalanus pavo r styliremis 1 Candacia bispinosa simplex Canthocalanus pauper r Centropages calaninus c elongatus r furcatus r violaceus Clausocalanus arcuicornis furcatus Copilia denticulata Corycaeus crassiusculus flaccus lautus limbatus pumilus speciosus Eucalanus attenuatus elongatus Euchaeta marina Euchirella brevis Farranula carinata a curta f gibbula rostrata Haloptilus acutifrons Haloptilus longicornis. . . . pluraosus spiniceps Heteramalla dubia Heterorhabdus spinifrons. Labidocera detruncata. . . Lucicutia Havicornis Mecynocera clausi Microsetella norvegica. . . rosea Neocalanus gracilis tenuicornis Oithona setiger similis spinirostris Oithonina nana Oncaea curta niinuta tenella venusta Paracalanus parvus Phaenna spinifera Pontellina plumata Pseudocalanus minutus . . Rhincalanus nasutus Sapphirina auronitens. . . nigromaculata Scolecithricella abyssalis. auropecten marginata Scolecithrix danae Undinula caroli darwinii The temperature was high at the surface, remained the same at 50 meters, and dropped 7?5 at 100 meters; the salinity increased and the hydrogen-ion concentration de- creased slightly. Twenty species were taken at the surface, 31 in the 50-meter tow, and 51 in the 100-meter tow. Thirty- seven species (56 per cent) were each confined to a single depth and 7 were present at all three depths. The 100-meter tow was slightly longer than the others and its volume was twice as large. This tow also contained one of the two records for Heteramalla dubia. Corycaeus, Farranula, and Oncaea were present in each of the tows, but Candacia and Oithona did not appear at the surface. 1 62 COPEPODS OF LAST CRUISE OF CARNECilE Station 154 October 31, 1929; 6° 42' N, 143° 22' \V; bottom depth, 5149 m; 64 species Depth of tow, m Temperature, °C Salinity, o/oo Volume of tow, cm' 50 100 Depth of tow, m 50 100 28.3 28.2 25.3 Density (<7tp) 21.6 21.9 23.5 34.1 34.1 34.8 Hydrogen-ion cone. (pH) 8.39 8.40 7,93 32 32 96 Length of tow, miles 0.1 0.1 0.1 Acartia danae negligens Acrocalanus gibber gracilis monachus Calocalanus pavo styliremis Candacia norvegica simplex Canthocalanus pauper. . . . Centropages calaninus. . . . elongatus Clausocalanus arcuicornis . furcatus Clytemnestra rostrata. . . . Copilia denticulata Corycaeus anglicus crassiusculus furcifer speciosus typicus Eucalanus attenuatus elongatus Euchaeta acuta marina Euchirella brevis curticauda pulchra Farranula carinata curta gibbula rostrata r f f f f r f r r a a f r r r a a c c Haloptilus longicornis. . . . plumosus Heterorhabdus spinifrons. . Labidocera detruncata. . . . Lucicutia clausii flavicornis Macrosetella gracilis Mecynocera clausi Megacalanus longicornis. . Microsetella norvegica. . . . rosea Neocalanus gracihs robustior tenuicornis Oithona pluniifera similis spinirostris Oithonina nana Oncaea media minuta notopa subtilis venusta Paracalanus aculeatus. . . . parvus Pontella tenuiremis PonteHina plumata Pseudocalanus minutus. . . Sapphirina nigromaculata . Scolecithrix danae Undinula caroli darwinii The temperature was high at the surface and dropped 3° in the 100 meters; the salinity increased and the hydrogen- ion concentration diminished slightly. Seventeen species were taken at the surface, 35 in the 50-meter tow, and 47 in the 100-meter tow. Thirty-seven species (58 per cent) were each confined to a single depth and 8 were present at all three depths. The fi\'e genera Candacia, Corycaeus, Farran- ula, Oithona, and Oncaea were each present in all three tows, but Oncaea was particularly abundant in the 100-meter tow. LISTS OF SPECIES BY STATIONS 163 Station 155 November 2, 1929; 4° 51' N, 146° 46' W; bottom depth, 5304 m; 74 species Depth of tow, m Temperature, °C Salinity, 0/00 X'olume of tow, cm' 50 100 Depth of tow, m 50 100 27^7 27.7 27.2 Density (irtp) 22.4 22.6 23.1 ,U ') -U.O .15.0 Hydrogen-ion cone. (pH) 8.2<) 8.30 8.30 64 96 128 Length of tow, miles 3.5 3.7 3.4 Acartia danae longiremis negligens Acrocalanus gibber gracilis longicornis monachus Calocalanus pavo styliremis Candacia bispinosa catula norvegica simplex Canthocalanus pauper. . . . Centropages calaninus. . , . elongatiis violaceus Clausocalanus arcuicornis . furcatus Clytemnestra rostrata. . . . scutellata Copilia denticulata quadrata Corycaeus andrewsi crassiusculus flaccus lautus longistylis pacificus speciosus Eucalanus attenuatus elongatus Euchaeta acuta marina Euchirella brevis curticauda Farranula carinata 19 Farranula curta f gibbula rostrata c Labidocera detruncata f Lucicutia clausii flavicornis Macrosetella gracilis Mecynocera clausi r Megacalanus longicornis Microcalanus pygmaeus r Microsetella norvegica c rosea Miracia efferata Neocalanus gracilis c robustior tenuicornis c Oithona plumifera similis a Oithonina nana Oncaca curta 3 minuta a notopa venusta a Paracalanus aculeatus parvus f Pennella sp., copepodid Pontclla cristata r Pontellina plumata f Pseudocalanus minutus Rhincalanus nasutus r Sapphirina auronitens r metallina nigromaculata r opalina Scolecithrix danae Undinula caroli darwinii The temperature was high at the surface and fell only 0?5 in the 100 meters; the salinity and hydrogen-ion con- centration also remained practically unchanged. Thirty-four species were captured at the surface, 46 in the SO-meter tow, and 52 in the 100-meter tow. Thirtj'-three species (43 per cent) were each confined to a single depth and 16 were present at all three depths. Candacia, Corycaeus, Farranula, Oithona, and Oncaea were present in each of the tows and quite evenly distributed. The 100-meter tow contains the only records for Candacia catula and Pennella during the entire cruise. The latter was in the free-swimming copepodid stage and the species could not be determined. 164 COPEPODS OF LAST CRUISE OF CARNEGIE Station 156 November 4, 1929; 3° 01' N, 149° 46' W; bottom depth, 4953 m; 78 species Depth of tow, m Temperature, °C Sahnity, 0/00 Volume of tow, cm' 50 100 Depth of tow, m 50 100 27.6 27.0 26.3 Density (-nine species (50 per cent) were each con- fined to a single depth and 8 were present at all three depths. Corycaeus, Farranula, Oithona, and Oncaea were found in each tow, but Candacia onl>- in the 100-meter tow, which also con- tained the only record for Dysgamus atlanticus, a parasitic form tliat sometimes lea\es its host and swims about freelv. LISTS OF SPECIES BY STATIONS 165 I Station 157 November 6, 1929; 1° 48' S, 152° 22' W; bottom depth, 4693 m; 71 species Depth of tow, m Temperature, °C Salinity, 0/00 X'okmie of tow, cm' 50 100 Depth of tow, m 50 100 27,0 27.0 26.8 Density (o-,.p) 22.8 23,1 23.5 35.2 35.2 35.4 Hydrogen-ion cone. (pH) 8.27 8.32 8.30 32 80 64 Length of tow, miles 0.4 0,9 0.9 Acartia danae longiremis Acrocalanus gibber gracilis monachus Aegisthus spinulosus Calanus minor propinquus Calocalanus pavo styliremis Candacia bispinosa simplex Canthocalanus pauper. . . . Centropages calaninus. . . . elongatus furcatus Clausocalanus arcuicornis. iCopilia denticulata quadrata Corycaeus clausi crassiusculus dubius f urcifer longistylis ovalis spcciosus typicus Eucalanus attenuatus elongatus Euchaeta marina Euchirella brevis curticauda Farranula carinata curta gibbula rostrata Haloptilus acutifrons. . . . longicornis Labidocera detruncata. . . Macrosetella gracilis oculata Mecynocera clausi Megacalanus longicornis . Microcalanus pygmaeus. Microsetella norvegica. . . rosea Miracia efferata Neocalanus gracilis. ...-., robustior tenuicornis Oithona plumifera robusta setiger similis spinirostris Oithonina nana Oncaea media minuta tenella venusta Paracalanus aculeatus. . parvus Pontellina plumata Pseudocalanus minutus. Rhincalanus cornutus. . . nasutus Sapphirina auronitens. . . nigromaculata Scolecithrix danae Undinula caroli darwinii The temperature was high at the surface and fell only 0?2 in the 100 meters; the salinity and hydrogen-ion con- centration also remained almost constant. Thirty-eight spe- cies were captured at the surface. SO in the 50-meter tow, and 36 in the 100-meter tow, an exceptionally uniform vertical distribution. Thirty-one species (44 per cent) were each confined to a single depth and 13 were present at all three depths. Candacia, Corycaeus, Farranula, Oithona, and Oncaea were all present in each tow. The two deeper tows were more than twice the length of the surface tow and their \olume was proportionalh' larger. The 50-meter tow con- tained a large number of development stages. i66 COPEPODS OF LAST CRUISE OF CARNEGIE Station 158 November 8, 1929; 6° 33' S, 154° 58' \V; bottom depth, 4065 m; 54 species Depth of tow, m Temperature, °C Sahnity, o/oo X'olume of tow, cm^ 50 100 Depth of tow, m 50 100 28.1 28.1 27.6 Densitv (i7tp) 22.7 23.0 23.6 35.5 35.5 35.8 Hvdrogen-ion cone. (pH) 8.34 8.39 8 39 32 80 32 Length of tow, miles 0.7 2.2 2.2 Acartia clausii danae longiremis Anomalocera patersonii . . . Calanus helgolandicus. . . . Calocalanus pavo styliremis Candacia aethiopica bispinosa simplex truncata Canthocalanus pauper. . . . Centropages calaninus. . . . elongatus furcatus Clausocalanus arcuicornis. Corycaeus anglicus crassiusculus pumilus speciosus typicus Eucalanus attenuatus elongatus Euchaeta marina Euchirella curticauda Farranula carinata curta Farranula gibbula rostrata r Labidocera detruncata r Lucicutia flavicornis Mecynocera clausi r Microcalanus pygmaeus r Microsetella norvegica rosea r Neocalanus gracilis tenuicornis Oithona plumifera r similis spinirostris r Oithonina nana r Oncaea minuta notopa r \-enusta c Paracalanus parvus c Pontellina plumata Pseudocalanus minutus Rhincalanus nasutus Sapphirina angusta auronitens Scolecithricella marginata spinacantha, n. sp Scolecithrix danae Undinula darwinii The temperature was high at the surface and fell only 0?5 in the 100 meters; the salinity and hydrogen-ion con- centration also changed but little. Twenty-one species were captured at the surface, 37 in the 50-meter tow, and 29 in the 100-meter tow. Twenty-eight species (52 per cent) were each confined to a single depth and 7 were present at all three depths. Corycaeus, Farranula, Oithona, and Oncaea were found in each of the tows, and especially at the surface, but Candacia did not appear in the surface tow. This latter tow contains one of the few records (or Anomalocera patersonii during the cruise. The 50-meter tow contains the first record of the new species Scolecithricella spinacantha (cf. sta. 159). LISTS OF SPECIES BY STATIONS 167 Station 159 November 11, 1929; 9° 24' S, 159° 01' W; bottom depth, 5545 m; 76 species Depth of tow, m Temperature, °C Salinity, 0/00 \olume of tow, cm' 50 100 Depth of tow, m 50 100 28.6 28.5 28.0 Density (atp) 22.7 23,0 23.4 35.7 35.7 35.7 Hvdrogen-ion cone. (pH) 8.37 8.38 8.37 32 48 64 Length of tow, miles 0.8 1.1 1.1 Acartia clausii danae longiremis negligens Aetideus armatus Amallothrix propinqua Calanus minor Calocalanus pavo plumulosus styliremis Candacia aethiopica bispinosa norvegica simplex Canthocalanus pauper Centropages calaninus elongatus furcatus Clausocalanus arcuicornis furcatus Clytemnestra rostrata scutellata Corycaeus agilis catus crassiusculus flaccus lautus ovalis pacificus robustus speciosus Danodes plumata, n, gen. and n. sp. Eucalanus attenuatus elongatus Euchaeta marina Euchirella brevis curticauda Farranula carinata f 4 1 a r9 f c a c Farranula curta gibbula rostrata Haloptilus longicornis. . . . spiniceps Heterorhabdus spinifrons. Labidocera detruncata. . . Lucicutia flavicornis Macrosetella gracilis Mecynocera clausi Microcalanus pygmaeus. . Microsetella norvegica. . . rosea Neocalanus gracilis tenuicornis Oithona plumifera siniilis spinirostris Oithonina nana Oncaea media minuta notopa venusta Paracalanus parvus Pontella cristata Pontellina plumata Pseudocalanus minutus. . Rhincalanus cornutus. . . . nasutus Sapphirina angusta auronitens Scolecithricella abyssalis. bradyi marginata spinacantha, n. sp. . . Scolecithrix danae Undinula caroli darwinii f f c r f f a c r r r a a c a a c c f c f f a a c f f c The temperature was high at the surface and fell only 0?6 in the 100 meters; the salinity and hydrogen-ion con- centration remained practically unchanged. Twenty-six spe- cies were taken at the surface, 50 in the 50-meter tow, and 51 in the 100-meter tow. Thirty-five species (47 per cent) were each confined to a single depth and 9 were present at all three depths. Candacia, Corycaeus. Farranula, Oithona, and Oncaea were present in all tows, but more abundant in the deeper tows. The 50-meter tow contained the new sjaecies Scolecithricella spinacantha, and is the second of two adjacent stations where it appeared. The deeper tows were a little longer than the surface tow and their volume was larger. i68 COPEPODS OF LAST CRUISE OF CARNEGIE Penrhyn Island, Lagoon November 10, 1929; 9° 02' S, 157° 59' W; 10 species Acrocalanus gracilis 1 Farranula carinata r rostrata 2 Mesocyclops leuckarti a Oithona similis 3 Oncaea minuta r venusta f Paracalanus parvus a pygmaeus c Undinula vulgaris 1 This was an anchorage tow, at the surface, between stations 159 and 160, and yielded 10 species, none of which are worthy of comment except Mesocyclops leuckarti. All the other species in this list are typical pelagic forms, and here is an equalh' t>-pical fresh-water form found abundantly in their midst. Volume of tow, 32 cm'. Station 160 November 13, 1929; 10° 54' S, 161° S3' W; bottom depth, 2614 m; 74 species Depth of tow, m Temperature, °C Salinity, o,'oo Volume of tow, cm' 50 100 Depth of tow, m 50 100 28.5 28.5 28.5 Densitv (