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 



