COPEPODA 



233 



maxillipeds are like those of the female ; the comparative length of the main divisions is 55, 65 and 

 32; the endopodite is somewhat shorter, and its setae are less strong. The sensory seta of the second 

 basipodite is three to four times as long as wide, curved, and somewhat attenuated; it is thus well 

 distinguished from the short one of the female, as well as from the comparatively long and straight one 

 of the male in O. cristatus. 



The first pair of legs differs from that of the female by the want of spines on the posterior sur- 

 face of the Re I, and by three spines only in Ri. The second pair of legs is scarcely different from 

 that of the female. The third pair of legs is in main features like that of the female; the third outer 

 segment is of usual structure, and the armature of the posterior surface is like that of O. magnus. 

 The fourth pair of legs was very defective. 



The fifth pair of legs, like that of O. cristatus, consists of a short right leg extending 

 scarcely to the end of the first segment of the left side, and of a long and slender left leg, which 

 extends distinctly beyond the end of the abdomen (text-fig. 74 f) ; the right leg has, as seen in text-fig. 

 74 h, three fairly long and broad proximal segments in addition to a rudimentary terminal one, con- 

 tinued into a short spine. The left leg consists, as seen in figure, of five elongated segments like those 

 of O. cristatus ; the third outer segment is, however, as seen in text-fig. 74 i, less slender, and has in 

 addition to the terminal seta a distal outer one. 



Occurrence. The Thor has taken a male and a female of this species "/ 7 1904 St. 183 6i3O 

 L. N. I7o8 L. W. Yt. 1800 M. Wire. 



Distribution. Previously a single specimen (?) has been gathered by the Monaco St. 1849, 36i7 

 L,. N. 2828 L. W. 03000 M., on the west coast of Ireland (55 L,. N. 10 L. W. at 1150 fathoms) and by 

 the Siboga at 3 L. S. 127 L. E. 



Remarks. My specimens do not differ from Sars' short description, and agree with Farran's 

 specimens in the shape of the genital somite, but differ by the shape of the fifth pair of legs, which 

 is not "five-jointed" on the one side. From Scott's figures they differ by minor points in the structure 

 of the antennulae, but especially by the third segment of the fifth foot, which has a distal Se in ad- 

 dition to an undivided St; as, however, the fifth foot seems to vary from the one specimen to the 

 other, there is not at present sufficient justification for separating the two species from each other. 



75. Onchocalanus affinis n. sp. 

 (Text-figs 75 a e and 76 a d). 



Description. f$>. Size of female from Thor St. 183 was 6-3 mm.; anterior division 5-09 mm.; 

 urosome 1-4 mm. 



The body is somewhat more slender than in the preceding species. The head is more suddenly 

 raised; the basal portion, which is more powerful than in the preceding species, is directed more 

 downwards (text-fig. 75 a). The first and the fifth tergites are only indistinctly marked in front; the 

 lateral corners are triangularly produced and obtusely rounded. 



The abdomen (text-fig. 75 b) differs from that of the preceding species by the shape of the 

 genital somite; dorsally the somite, somewhat in front of the middle, is rather suddenly wider than 



The Ingolf-Expcdition. III. 4. 3 



