234 



COPEPODA 



more anteriorly, but posteriorly it is of almost equal width. The comparative length of the three first 



abdominal somites and the furca is 75, 50, 30 and 22. 



The antennulae reach at least to the end of the third abdominal somite; the Sp of segment 24 



is one third removed from the tip of the segment, and is far from extending to the end of segment 



25; in other respects the antennulae are like those of the preceding species. The oral appendages are 



scarcely different from those of O. hirtipes; the com- 

 parative length of the main divisions in the maxilli- 

 peds is 85, 100 and 57; the sensory seta of the second 

 basipodite is fairly long like that of O. cristatus. 



The first pair of legs differs from that of O. hirti- 

 pes by the number of spines ; the endopodite has 4 spines ; 

 the exopodite has no spines in Re I, 7 spines at the 

 base of Si Re II, and in Re III 3, 6 and 6 spines near 

 the inner margin. The number of spines on the posterior 

 surface in the second pair of legs is somewhat greater 

 than in O. hirtipes\ the endopodite has in Ri II 8 -j- 



6 -f- 12 spines. In the structure of the third and fourth 

 Text-fig. 75. Onchocalanus affinis n. sp. f9- 



a. Rostrum x 18. b. Abdomen x 18. c. Maxilla sin. in legs no difference from the preceding species was' ob- 

 anterior view X 150. d-e. Pes V sin. et dext. X 59- served . The fifth p air of legs (te xt-figs 75 d-e) differs 



from that of the preceding species by the structure of the terminal spines of Re III; in the left leg 

 two terminal spines in addition to a Se were found; on the right side the Se is poorly developed, but 

 a fairly strong Si was found. The anterior surface is, as in O. hirtipes, almost completely smooth. 





fo*. Size of male from Thor St. 180 was 5-19 mm. ; anterior division 4-1 mm.; urosome 1-09 mm. 



The shape of the body is like that of the preceding species; the lateral 

 corners are more rounded and less produced than in the female. The com- 

 parative length between the abdominal somites and the furcal branches is 30, 

 45, 36, 24, 2 and 15. The antennulae almost reach to the end of furca; they show 

 the usual differences from those of the female. The antennae, mandibulae and 

 maxillulae are scarcely different from those of the adult female. The maxillae 

 differ by the structure of some of the sensory setae of the endopodite (text- 

 figs 75 c). The maxillipeds are like those of the preceding species, but the 

 sensory seta is shorter than in the preceding species; the comparative length 

 of the main divisions is 75, 80 and 42. The natatory legs are scarcely different Text-fig. 76. 



r . , r ii r i Onchocalatms affinis 11. sp. fH 1 . 



from those of the female. 



a. Pes V X 1 8. b. Basal 



The fifth pair of legs (text-figs 76 a b) is only in minor points dif- segments of pes V x 59- 



c. Pes V Re III dext in 

 ferent from that of O. rnrhpes; the right leg extends somewhat beyond the posterior view x 150. d. Re 



first segment of the other side. The terminal segment of the right leg is m sm - x ! 5- 



somewhat bigger than in the preceding species (text-fig. 76 c); the third outer segment has on the left 

 side, as seen in text-fig. 76 d, a somewhat different shape from that of O. hirtipcs. 







