220 Notes on North American Cr^tstacea. 



its outer angle, and by the broad, lamelliform dactyles of the 

 first three pairs of ambulatory feet. 



In the dismemberment of the genus Lwpa^ the old name 

 should strictly have been retained for this group called Nep- 

 tunus by De Haan. But as that author had a right to restrict 

 the name as he did, to Lupa forceps^ it can scarcely now be 

 changed. 



IVeptiinus isayi. 



Lu-pa pelagica Say, Jour. Acad. Nat. Sci. Philad. i. 97. 

 Lupa sayi Gibbes, Proc. Am. Assoc. 1850, p. 178. 



Found among floating sargassum in the North Atlantic 

 Ocean, and not unfrequently washed ashore in considerable 

 numbers on the Florida Reels. 



Callinectes.* 



Under this generic name we propose to distinguish the 

 common American Lupa diacantha. It cannot be placed in 

 any group yet indicated without violence to its characters. 

 "With the broad carapax, low front, and general habit of Nep- 

 tunus, the genus now proposed is quite distinct in its external 

 maxillipeds, the meros-joint of which, though short, is sharply 

 prominent and curved outward at its antero-external angle. 

 Also, the male abdomen in the narrowness of its terminal 

 half, has a form found in no other genus of Lupidae, except 

 perhaps Euctenota Gerst., a genus characterized by its narrow 

 front and dentated orbits. 



Callinectes diacanthus. 



Lupa diacantha (Latr.) M. Edw. ; Hist. Nat. des Crust, i. 451. 

 We have been unable to find constant differences between 



* KaX5f, strenuTM j vriKrm^ aatatojr. 



