No. XV. 



Description of a New Species of the Genus Jlstacus. By B. 

 Harlan, M.D. fyc. Bead April 3d, 1829. 



A. Blandingii. 



Rostrum mucronate, canaliculate, slightly notched at the 

 extremity : a spine behind each eye ; arms tuberculated ; fin- 

 gers unequal. 



Inhabits the southern states, where it is common in the 

 marshes and rivulets. 



Cabinet of the Academy of Natural Sciences. Presented 

 by Dr W. Blanding, Camden, S. C. 



Description. — The hands and arms, and sides of the body 

 tuberculated ; conspicuously large on the hands : thorax with 

 a small spine on the side, behind the transverse arcuated 

 band ; first and second joints of the peduncles of the exterior 

 antennae furnished with each a single spine : rostrum elonga- 

 ted, angular, attenuated anteriorly, and obsoletely notched 

 near the extremity, extending nearly to the tip of the third 

 joint of the peduncle of the exterior antenna, carinated on 

 each side of the base, and terminating in a post-ocular spine : 

 anterior feet, third joint very long, with a double longitudi- 

 nal series of spines beneath : carpus four-spined ; spines irre- 

 gularly distributed about the anterior margin : hands long, 

 tuberculated throughout; fingers elongated, slightly curved 



