42 THE VOYAGE OF H.M.S. CHALLENGER. 



The five segments of the trunk exposed behind the carapace rapidly diminish in 

 height posteriorly, and have all rather broad laminar epimera, somewhat projecting 

 laterally (see fig. 6). The first segment is very narrow, almost band-like, and the last 

 does not exceed the succeeding caudal segment either in height or in breadth. 



The tail is very slender, considerably longer than the anterior division of the body. 

 The form and relative length of the segments are very nearly as in Leucon. As in that 

 genus the last segment is rather short and obtusely produced posteriorly. 



The integuments are rather thin and without any distinct sculpturing, but beset with 

 scattered short hairs, especially on the tail. 



The antennulaa (see fig. 5) exhibit the structure and peculiar flexure characteristic of 

 the genus. They are rather stout and affixed to a fleshy segment lying immediately in 

 front of the upper part of the carapace, from which segment they, as it were, hang 

 down, forming a sharp elbow-like bend at the middle. This bend occurs between the 

 two outer joints of the peduncle, in such a manner that the last joint together with the 

 flagella is doubled upon the proximal part of the antennula, pointing obliquely 

 upwards. Of the flagella the inner one is fully as long as the first joint of the outer, but 

 only composed of a single joint bearing three strong spine-like bristles at the tip. The 

 outer flagellum is triarticulate and provided with several strong ciliated bristles, 

 especially along the edges of the first joint ; at the tip this flagellum bears the usual two 

 ribbon-like sensory appendages, which, however, are rather short, scarcely exceeding the 

 simple apical bristles in length. 



The first pair of legs (fig. 8) are rather strong, projecting considerably in front of 

 the carapace, and when fully extended about as long as the whole anterior division of 

 the body. The basal joint is slightly curved and furnished on both edges of the distal 

 part with several ciliated bristles. The terminal part of the leg is considerably longer 

 than the basal and exhibits the usual well marked geniculate bends ; it is furnished along 

 the outer edge with scattered and rather long setse, which are finely ciliate. Of the 

 joints the penultimate is the longest, whereas the terminal joint is comparatively short 

 and much compressed, with numerous claw-like spines at the obliquely truncated apex. 

 The exopodite does not reach to the end of the basal joint and has the terminal part 

 divided into five setiferous articulations. 



The second pair of legs (see fig. 5) are comparatively stronger than in Leucon, but 

 as in that genus only sex-articulate, the ischial joint not being distinctly defined. The 

 terminal joint is almost linear and provided with a number of diverging spines, arranged 

 in a double row. 



The third pair of legs (ibid.) have the exopodite well developed and of the same 

 structure as in the two preceding pairs, whereas the two posterior pairs (figs. 10, 11) are 

 simple and rather small, especially the last pair. 



The uropoda (see fig. 12) are rather strong, fully as long as the two last caudal 



