Notes on North American Crustacea. 209 



the orbit. Chelipeds rather short and stout, rugulose above and exter- 

 nally. Length of carapax, 0.52 ; breadth, 0.82 inch. 



It approaches nearly to X. sternheixjhii in its smooth carapax, 

 but may be easily distinguished by its obtuse antero-lateral 

 margin. 



Found at Cape St. Lucas, where it is extremely abundant, 

 according to Mr, Xantus. 



Xaiithodiiiis aiuericanus. 



Chlorodius americanus Sauss. ; Crust, nouv. des Antilles et du 



Mexique, p. 14, pi. i. f, 5. 



In a criticism of M. De Saussure's " Memoires" (Silliman's 

 Am. Jour. Sci., 2nd Ser. xxvii. 446), we have considered this 

 species identical with C. floridanus Gibbes. Having recently, 

 however, secured numerous specimens of it, we are enabled to 

 acknowledge the error. It is entirely distinct ; — the carapax is 

 much broader and more rounded at the lateral angle, the lobules 

 are more protuberant, the surface is punctate, not transversely 

 striated, the lateral teeth are less acute, and the body and feet 

 generally, are much less hairy. The frontal margin is trans- 

 versely canaliculated as in C. floridanus. 



As this species has a strong ridge upon the palate, I have 

 arranged it above in Xanthodius. 



Found at the Tortugas, Fla., Capt. Woodbury; and at Barba- 

 does, T. Gill. 



Chlorodius lloridanu!§. 



Chlorodius floridanus, Gibbes; Proc. Am. Assoc. 1850, p. 175. 



This species has much resemblance to the Pacific C exaratus, 

 with wdiich it is confounded by Dana (U. S. Expl. Exped., 



