134 



COPEPODA 



keel. The body is rather slender and in dorsal view somewhat attenuated towards the front; the lateral 

 corners are rounded (text-figs 35 d — e). The abdomen, which is at least one third as long as the an- 

 terior division, is long and slender. The genital opening is placed on the left side; the fifth somite is 

 scarcely visible from above; the caudal rami are short (only half as long as the fourth somite, rounded 

 and about as long as wide). The terminal setae are distinctly longer than the abdomen, and the Si is 

 one fourth as long as St. 2. 



The atticnmilac extend about to the end of the third abdominal somite; the segments 8 '^^ 9 are 

 partly fused with 10, and 12 with 13, but the segments 20 and 21 are well separated on both sides. 

 The measurements are very like those of the female; the appendages are practically like those of 

 Aetidius. The antennae are scarcely different from those of the female; the manducatory part of the 

 mandibulac is well developed and rounded, but soft-skinned, without any teeth, while the terminal setae 

 of the palps are more powerful than in the female. The niaxillulac have no setae in Li i — 2, but 3 

 in Li 3; the number of setae in the third basipodite and the Ri is as in the females, but they are more 

 slender. The Re has 10 powerful setae, which were all of equal length. The maxillae form an angle- 

 shaped soft-skinned organ, in which distally soft-skinned, irregular twisted appendages are found. In 

 the second basipodite of the maxillipcds two setae are found in the fourth lobe; the third basipodite 

 is enlarged basally, and attenuated towards the end; the setae of the endopodite are fewer in number 

 and less powerful. 



The^ Jirsl pair of legs has a well developed articulation between Re I — II, and the Se Re II is 

 short and strong, and far from reaching the middle of following segment; in other respects the natatory 

 legs are scarcely different from those in the female. 



The right leg of t\i& Ji/th pair (fig. 3 b) has a short second basal segment, which is fused with 

 the corresponding one of the left side, and is strongly produced outwards, and a much longer and wider 

 third basal segment. The right endopodite (fig. 3 e), which extends to the end of Re I 00 II, is rather 

 elongated, distally slightly curved and, as shown in fig., somewhat hollowed; its anterior surface is 

 distinctly striated, and marginally we observe a basal tooth, followed by a distinct striated keel, which 

 is most elevated in the middle (figs 3 c and e). The Re I <n> II of right leg, which are almost completely 

 fused (figs 3 c — d), have in the proximal part the inner surface striated, and the outer one mounted with 

 a few rounded rudimentary teeth, followed by an elongated lamina, and lastly a distinct tooth ; the distal 

 portion (Re II) is somewhat attenuated, and has medially a somewhat contorted, irregular lamella; the R III, 

 which is comparatively short, has its inner surface somewhat excavated, and has the posterior inner margin 

 lamellous. The le/t leg (fig. 3 b) has a short second basal segment, but a long and wide third one; the 

 left endopodite (text-fig. 35 f) is long and slender, reaches distinctly beyond the middle of Re (not seen 

 in fig. 3 b), is widest at the base and is distally enlarged to a rounded lamella (text-fig. 35 f). The left 

 exopodite has a fairly short, somewhat curved Re I, a rather short Re II which terminally possesses 

 a strong spine bearing a basal accessor}' tooth (fig. 3 f), and a moderately long Re III, which possesses 

 a long terminal seta and a group of fairly long setae anteriorly and interiorly; the last segment is 

 laterally connected with the Re II by a real articulation, but medially by a wide, soft membrane of a 

 somewhat complicated structure. 



