COPEPODA 161 



somewhat longer; the Basp. 2 has 4, and the Ri at least 5 setae. The Re has 10 -j- i setae. The max- 

 illae are quite rudimentary soft-skinned, somewhat twisted organs possessing the usual number of 

 lobes, which bear soft appendages, on the distal lobes most like setae. The maxillipeds are less powerful 

 than those of the female, the Li I of the basipodite i os 2 has one hair, Li 2 one short hair, Li 3 two 

 hairs and Li 4 a single hair in addition to a hooked organ surrounded by fine hairs like that of E. 

 bisinuata Far ran (PI. VI fig. nc). 



The second pair of legs differs distinctly from that of the female by the short Se Re II, which 

 only reaches the end of the segment, far removed from the base of Se i Re III. 



The Re II III sin. of the fifth pair of legs (PI. VI fig. 3d) are in the main like Giesbrecht's 

 fig. 24 (Taf. 16), differing from Sars' by two not one, rows of serrations, between which the seg- 

 ment is distinctly more hollowed than in the two following species. The left endopodite consists of 

 two segments (text-fig. 45 e). 



The epistoma and labrum are in lateral outline seen to be distinctly lower than those of the 

 females ; by further examination (PL VI fig. 3 e) it was found to be poorly developed, without labial 

 lamina and distinct labial lobes; the complicated system of hairs found in the females seems to be 

 completely wanting. 



Y $ (St. V). Size of specimen from Thor 81.183: the total length 5-57 mm. ; anterior division 

 (2-46-)- 179) 4-25; urosome 1-42. 



The shape of the anterior portion differs from that of the f $ by triangularly pointed lateral cor- 

 ners (text-figs 45 f g). The abdominal somites show the usual differences; in constrast to the f$, the Si 

 of the furca is distinctly shorter than the St. 2 (text-fig. 45 h). The antennulae are comparatively shorter, 

 but the arrangement of the appendages is completely like that of the f .; the measurements are, 

 however, slightly different; the segments 24^25 are at least as long as the segment 19, not ra shorter, 

 as the segment 23 is n as long as, not ri as short as, the segment 16. The Re of the maxillulae 

 possess only 10 setae. The Re I II of the first pair of legs are completely fused without trace of 

 segmentation. 



The male of this stage is easily distinguished from the female by the presence of a fairly well 

 developed two-branched fifth pair of legs (text-figs 45 g and i). 



Y ? (St. IV). Size of a big specimen from St. 183 was 3-6 mm.; anterior division (17 + 1-0) = 

 27 ; urosome 0-90 mm. 



This stage differs from the preceding one by the urosome, which consists of three somites only 

 (text-figs 45 j k), of which the last is the longest, the first the shortest; the subapical seta is, as in 

 the preceding stage, shorter than St. 2. The antennulae have the appendages like the adult females, and 

 the measurements show corresponding differences; the segments 24^ 25, f. inst, are distinctly 1-2 as long 

 as the segment 19. The Re of the maxillulae possess only 9 setae, as usual in this stage. The exopodite 

 of the first pair of legs is alone unsegmented, as not only Re I II are fused but also Re II III. The 

 Re II III of pes II III are fused with 3 Se, of which Se i Re II oo HI pes II is comparatively long, 

 probably corresponding to Se Re II. The Ri II III are fused in pes III IV. 



The Ingolf-Expedition. III. 4. 21 



