Notes on North American Crustacea. 223 



and ciliated. Length of carapax in a female, 0.54 ; breadth, 1.05 

 inch. 



Very common on the beaches of Cape St. Lucas. J. Xantus. 



Achelous tuberculatus, uov. sp. 



Carapax inconspicuously pubescent, surface uneven, with the pro- 

 tuberant parts granulated. There are from four to six small tubercles 

 on the gastric region, two on the cardiac, and two on the inner part of 

 each branchial region. Front rather prominent, convex, four-toothed ; 

 teeth subequal, the median ones most projecting and more greatly 

 6'eparated from each other than from the lateral ones. Eyes of moderate 

 size, with the cornea but little thicker than the peduncle. Antero- 

 lateral margin nine-toothed, with the posterior tooth or spine very long, as 

 long as the space occupied by the next five teeth in front of it. Pos- 

 terior angle of the carapax armed with a hooked spine, directed upward 

 and forward. Meros-joint of external maxillipeds rather less produced 

 than usual. Chelipeds slender, with spines as in the preceding species ; 

 hand very slender. Dactyli of ambulatory feet as in A. xantusii. 

 Length of the carapax in a female, 0.52 ; breadth, 1.20 inch. 



Common at Cape St. Lucas. J. Xantus. 



Achelous depressirrons. 



Amphitrite depressifrons Stimpson, An. Lye. Nat. Hist. N. Y., vii. 58. 



We have received a large number of fine specimens of this 

 species from the ojficers stationed at the Tortugas, Fla., which 

 enable us to amend the specific character previously published, 

 and to add further remarks. The largest of these specimens is 

 an inch and a half in width. The carapax is pretty uniformly 

 mottled and clouded with purplish-grey, but is lighter at the 

 middle. There is always a dark median spot on the intestinal 

 region. Front very little prominent. Hand remarkably short 

 and compressed, with the spine of the superior margin situated 



