110 Notes on North American Crustacea, 



from the supra- oi'bital margin by a small notch ; its margin is simply 

 granulated, and there is a slight channel running parallel with it and 

 se^Darating it from the frontal region. The orbital margin is unarmed 

 except by small tubercles or graniiles, and has a single slight fissure 

 at the middle above. The antero-lateral margin is sharply defined, 

 almost limbed ; and is armed with three very slightly prominent 

 teeth, besides the angle of the orbit, and a broad lobe posterior to it, 

 neither of which project beyond the general outline ; the three 

 teeth are each composed of two or three denticles, of about the size 

 of the tubercles of the dorsal surface. There is no subhepatic tooth. 

 The ridge of the endostome is almost obsolete. Chelipeds large, granu- 

 lated ; carpus and hand usually covered on the outside with a dense 

 tuft of algoid growth. 



Dimensions of a male specimen : Length of carapax. U 1 6 ; breadth, 

 0.20 inch. 



This species is chiefly remarkable for tlie absence of a sub- 

 hepatic tooth, and the character of the antero-lateral margin, 

 which approaches somewhat in appearance that of P'duui- 

 noides, though much shorter. 



Cape St. Lucas : J. Xantus. 



Acidops nov. gen. 



Carapax broad, smooth, with convex antero-posteiiov and nearly 

 plane transverse dorsal outline ; surface nearly even. Antero-lateral 

 margin short, acute, with three inconspicuous teeth, besides the 

 angle of the orbit. Eyes and orbits elongated, resembling somewhat 

 those of certain Macrophthalmoids. Orbits destitute of teeth or 

 fissures. Eye -peduncles flattened, with an acute anterior edge con- 

 tinuous with that of the margin of the carapax. The basal joint of 

 the external antennae fills the hiatus of the orbit and just reaches the 

 fi"ont. Chelipeds small. Ambulatory feet broad and compressed, 

 except the terminal joint, which is narrow. Abdomen of the male 

 with the third joint much produced on either side. Male appendages 

 of the first pair broadly laminate at base, geniculated at the posterior 

 third of their length, and tapering to a fine point, somewhat iiicurved 

 toward the extremity, and reaching to the penult segment of the 



