302 A IIISTOEY OF RECENT CRUSTACEA 



produced ; the uropods with the peduncle elongate, 

 and the inner branch generally two-jointed. 



Cyclaspis, Sars, 1865, agrees with the above characters 

 of Cuma, except that the carapace is swollen, 

 almost globular, the eye is not always present, 

 the peduncle of the uropods is not greatly elon- 

 gate, and the inner branch is one-jointed. 



Iphinoe, Spence Bate, 1856, has the body slender, com- 

 pressed, five segments of the trunk distinct 

 behind the carapace ; the eye distinct ; the second 

 joint of the third maxillipeds produced ; the second 

 joint of the inner branch of the uropods elongate. 



Cumopsis, Sars, 1879, has five segments of the trunk 

 distinct behind the carapace ; the eye well de- 

 veloped ; the second joint of the third maxilli- 

 peds not produced. The second and third pairs 

 of perasopods have one-jointed setiferous exopods. 



StepJianomma, Sars, 1871, is uniquely devoid of the 

 frontal bifurcating suture ; it has five segments of 

 the trunk distinct behind the carapace. The eye 

 (in the type species, StepJianomma Goe'sii, Sars) 

 forms a coronet or circlet of eleven ocelli. 



Of the genera thus briefly distinguished, Ouma, ' a 

 wave,' has given its name to the whole sub-order, although 

 not in fact the earliest named genus in it. Cuma scor- 

 pioides (Montagu, 1804) is a British species. The cara- 

 pace is strong and strongly ridged longitudinally. The 

 inner branch of the uropods is two-jointed. In Bell's 

 ' History of the British Crustacea ' a lamentable confusion 

 is made. It quotes in full Goodsir's descriptions of his 

 own Guma Edwardsii and Milne-Edwards' Cuma Audouinii, 

 but, as Sars has pointed out, the figures copied under the 

 heading Cuma Audouinii belong to Cuma Edwardsii, and 

 vice versa. As a matter of fact Goodsir's Guma Edwardsii 

 is a synonym of Cuma scorpioides (Montagu). Bodotria 

 arenosa, Goodsir, is, I think, a distinct species of Cuma, 

 separated from the other four species of that genus by 

 having the inner branch of the uropod single-jointed. 



