DESCEIPTIi'JN riF GENERA AND SPECIES. 



Order CUMACEA. 



Familv I. Ctmid^. 



The most characteristic feature of tlii5 family is the total want, in both sexes, of 

 exopodites on the four posterior pairs of legs, a character not found in any other known 

 gronp of Cmnacea. These legs also exhibit a very simple structure, and possess only a 

 scanty supply of bristles. On the other hand, the males are distinguished, by the 

 presence of five pairs of weU-developed pleopoda, and there is only one other family. 

 Vaunthompsoniidse, whi;h agrees with the Cumidse in this respect, whereas the males of 

 all other known Cumacea either have a less number of these limbs, or want pleopoda 

 altogether, as in the females. As a character peculiar to this family may also be 

 mentioned the highly indurated and strong integuments, the full development of the 

 branchial apparatus, and the total want of a telson. 



Of the five genera comprised within this family, only the genus Cyclaspis is repre- 

 sented in the Challenger collection. 



Cydaspis, G. 0. Sars, 1864. 



Cydasph, G. O. Sars, Om den aljerrante Krebsdyrgnippe Cmnacea og dens noidiste Artery p. 8L 



Generic Characters. — Carapace large and swollen, almost globular, with the dorsal 

 bne strongly curved, and the pseudorostral projection very slight ; a distinct notch on 

 each side anteriorly beneath the latter projection. Ocular lobe more or less produced, 

 and usuallv having: at its end a distinct eve. Onlv four 5ea:ments of the trunk exposed 

 behind the carapace, the anterior rather large, the three others suddenly much narrower, 

 and scarcelv broader than the caudal segments. Tail very slender and elongate, last 

 segment obtuselv produced at the tip. Antennulse with one of the flageUa very s m all, 

 knob-shaped, the other biarticulate, and bearing two long sensory appendages at the 

 extremity. Posterior Hp with the lateral lobes armed at the tip with strong teeth. 



