STALK-EYED CRUSTACEA 79 



antennae have stiff hairs. They are short ; their basal 

 joint is flat, and forms the floor of the orbit ; the second 

 joint is flat, short and wide, especially in its terminal 

 portion ; the third joint is also flat, but smaller ; the 

 flagellum is much reduced. The external maxillipedes 

 have the antero-external angle of their fourth joint dilated, 

 and the antero-internal angle slightly notched for the 

 insertion of the next joint. 



The first pair of legs of the male terminates in fingers 

 with spoon-shaped tips, where they only meet when closed. 

 The hands are more or less compressed. The walking 

 legs are robust and slightly elongated ; their last joint is 

 sharp, and has below a few teeth. 



Range. — Atlantic and Pacific on the American Coast, 

 West Indies. 



Synopsis of the SrEciES. 



A. Carapace longer than wide. 



a. Orbital angles acute. 



a^. External anterior edge of extremity of basal joint 

 of external antennae toothed. 



a^. Fingers almost in contact along their entire length 

 when closed. — {O. aciileata.) 



b^. External anterior edge of extremity of basal joint 

 of external antennae not toothed. 



U^-. Fingers, when closed, touch only at tips. — {O. 

 Ihcnnijiierii.) 



B. Carapace wider than long. 



b. Teeth on antero-lateral margin about of equal 

 size. 



c". First pair of legs of male very long. — {O. laevi- 

 gata.) 



