Wotes on North American Crustacea. 229 



OCYPODOIDEA. 

 Oclasinitis brevifrons, nov. sp. 



A large species, allied to G. palustris, but the carapax is more convex 

 and less narrowed behind, with the H-shaped impression in the middle 

 deeper ; the front very short, broad and more rounded ; and the anterior 

 superciliary margin more convex and projecting from the posterior one. 

 On the inner side of the greater hand, the inferior oblique crest is 

 much more prominent, while the superior one is nearly obsolete. Length 

 of the carapax, 0.72; breadth, 1.07 inch. 



Found in a lagoon at Todos Santos, near Cape St. Lucas, 

 Lower California, by Mr. Xantus. 



Ocypoda occidentalism nov. sp. 



Of the same size, and not easily distinguishable from the 

 common 0. arenaria of the eastern coast. But the ambulatory 

 feet are less pilose, and the pubescence upon them is much 

 shorter. The gastric region is more coarsely granulated. These 

 being constant differences, observed in a large number of spe- 

 cimens, we have ventured to consider the western form speci- 

 fically distinct. 



Found in considerable numbers at Cape St. Lucas, by Mr. 

 Xantus. Mr. X. gives an amusing account of his method of 

 taking these crabs. His small dog finds their holes and 

 digs them out, bringing them uninjured to the feet of his 

 master. 



Grapsii§ mactilattis. 



Grapsus maculatus (Catesby), M. Edw., Mel. Carcin. p. 132, pi, vi.f. 1. 

 Grapsus pictus Latr., Gibbes, etc. 



Found at the Tortugas by Messrs, Wurdemann and White- 

 hurst, and is not uncommon on other parts of the Florida coast. 



