200 



COPEPODS OF LAST CRUISE OF CARNEGIE 



The second maxillae are stout and the last lobe of the basilar 

 part terminates in a very long and strong claw, curved back- 

 ward and ending in a sharp point. At the base of the claw 

 on the inside are two or three long setae. The terminal part 

 is folded against the base of the claw and is armed with five 

 or six sensory appendages and two long setae. The maxilli- 

 peds are long and slender; the proximal segment of the basal 

 part is somewhat swollen, with small setae on the inner 

 margin; the distal segment is narrower and a little longer, 

 with three setae nearer the basal end. The terminal part is 

 made up of five segments, the second one the longest, the 

 terminal one very minute. 



The exopods of the swimming legs are all three-segmented; 

 the endopods of the first four pairs have one, two, three, and 

 three segments respectively. The first legs have no spines on 

 the posterior surface; the terminal segment of the second 

 endopod has a proximal group of three and a distal group of 

 four spines in an oblique row. The second segment of the 

 third endopod has six spines and the end segment has five; 

 the second segment of the third exopod carries a transverse 

 row of very slender spines close to the base of the segment; 

 the second segment of the fourth endopod has two groups 

 of three spines each in a longitudinal row, and the third 

 segment has a transverse row of three spines near the distal 

 end. The fifth legs are uniramose, three-segmented, and en- 

 tirely destitute of hairs, whence the specific name. The ter- 

 minal segment is conical, with three minute spines at the tip 

 and one on the outer margin near the center. 



Total length, 2.25 mm; length of metasome, 1.95 mm; 

 width, 1. 15 mm. 



Type. U. S. Nat. Mus. no. 64004. 



Remarks. This is much the smallest species of the genus, 

 and looks more like Pachos than like any other Onchocalanits 

 species. The strong claw on the second maxillae, the bifurcate 

 rostrum, and the spines on the posterior surfaces of the 

 swimming legs necessitate the reference of the species to the 

 present genus. The species can be identified by the small 

 size, the pyriform shape, and the entire lack of hairs on the 

 fifth legs. 



Onchocalanus trigoniceps G. O. Sars 

 (Figure 96) 



[Onchocalanus trigoniceps G. O. Sars, Bull. Mus. oceanogr. 

 Monaco, no. 26, p. 20, igoS-l 



A single female of this species was taken in the vertical 

 tow from a depth of 1000 meters at station 64 in the south- 

 eastern Pacific. This is larger than cristatus, but lacks the 

 frontal crest, and is another deep-water species that stays 

 below the loo-meter level in the daytime. It has been re- 

 ported before from the Atlantic, the Mediterranean, and the 

 Antarctic oceans, but not from the Pacific. 



Genus PACHOS Stebbing, 1910 



Pachos punctatiim (Claus) 



[Pachysonia punctata Claus, Die frcilcliencleii Copepoden, p. 

 i63,pl. 25, 1863.I 



This species was found in a surlace tow between stations 

 I and 2, near the Sargasso region, and at nine widely sepa- 



rated stations in the Pacific, no two of them being consecu- 

 tive or even close together. It was taken in 2 surface tows, 3 

 50-meter tows, and 5 loo-meter tows, all the abundance 

 records being expressed in numerals. The inference from 

 these meager statistics would be that it is nowhere abundant 

 and that it prefers the deeper levels during the daytime. It 

 was originally reported by Claus (1863, p. 163) from Messina 

 in the Mediterranean, and afterward by Brady (1883, p. 121) 

 in the Challenger plankton from the Philippine Islands, and 

 by A. Scott (1909, p. 262) in the Siboga plankton from the 

 western tropical Pacific. As far as is known, the present is 

 the first record from the northern Atlantic. 



Pachos tuberosum (Giesbrecht) 



[Pachysoma tuberosum Giesbrecht, Atti R. Accad. Lincei, 

 Rome, ser. 4, vol. 7, sem. i, p. 478, 1891; Fauna und Flora 

 des Golfes von Neapel, vol. 19, pp. 612, 615, pi. 48, fig. 37, 

 1892.] 



This species was not found in the Atlantic plankton, but 

 appeared at four scattered stations in the tropical Pacific. It 

 was not present in any surface tow, but was taken in 2 50- 

 meter tows and 4 100-meter tows. These records are even 

 more scanty than those for the preceding species, but, as far 

 as they go, indicate that the species remains at the lower 

 levels during the daytime. It has been reported by Giesbrecht 

 (189 1, p. 478; 1892, p. 612) from the Gulf of Panama and 

 by Cleve (1904, p. 194) from the South Atlantic. 



Genus PACHYPTILUS G. O. Sars, 1920 



Pachyptilus abbreviatus (G. O. Sars) 



[Pontoptilus abbreviatus G. O. Sars, Bull. Mus. oceanogr. 

 Monaco, no. 40, p. 19, 1905.] 



The Carnegie plankton has yielded the first Pacific records 

 for this species, a juvenile male captured in the 50-meter tow 

 at station 39 and a single female from 100 meters at station 

 113. This species is considerably larger than either species of 

 Pachos. It lacks the small frontal projection, and the endo- 

 pod of the fifth legs is one-segmented. Hitherto, Pachyptilus 

 abbreviatus has been reported only from the temperate 

 Adantic by Sars (1925, p. 319) and Rose (1929, p. 36), the 

 latter stating that all the species of this genus live at great 

 depths in the ocean. 



Genus PANDARUS Leach, 18 16 



Pandarus satyrus Dana 



[Pandarus satyrus Dana, Proc. Amer. Acad. Arts and Sci., vol. 

 2, p. 59, 1S49; U. S. Exploring Exped., 1S3S-1842 (Wilkes), 

 vol. 14, pt. 2, Crustacea, p. 1367, 1853; pi. 95, fig. la-c. 18=55.] 



Fifteen specimens were taken from the fins and skin of a 

 large shark captured at station no. This species, named 

 zygaenae by Brady (1883, p. 134), is usually found on sharks 

 of the genus Zygaena. The present host was not recorded, 

 but may well have belonged to that genus. Dana's (1849, 

 p. 59) original specimens came from the central tropical 



