1818.] CRUSTACEA OF THE UNITED STATES. 243 



raised lines near the middle, which are recurved at tip, 

 and an outer costal margin; tail subquadrate, with an im- 

 pressed longitudinal line, entire at tip. 



Inhabits. Georgia. 



Cabinet of the Academy. 



Length two inches and a quarter. 



Found on an oyster bed near the edge of the water at 

 low tide, and appears to be rare. Its analogue of Great 

 Britain, upon which this genus was founded by Dr. Leach, 

 discovered by Mr. Montague, and by him described in 

 the Transactions of the Linnean Society of London, is 

 also very rare, and inhabits the subterraneous passages 

 of the Solens or Razor shells; our species is very similar 

 to that, but differs from it more especially in having the 

 extremity of the tail entire. 



Genus ALPHEUS of Fabricius> 



Feety two anterior pairs didactyle; carpus of the se^ 

 cond pair divided into several joints. 



SPECIES. 



1. A. * heterochcvlis. Hands of the anterior feet very 

 unequal, larger one deformed and having a very small 

 transverse carpus; rostrum simple, spiniform, acute. 



Inhabits coasts of the southern states. 



Cabinet of the Academy, and Museum of South Ca- 

 rolina. ' 



Thorax glabrous, unarmed; rostrum carinate in the 

 middle and terminating in an acute point which nearly at- 

 tains the tip of the first joint of the inner peduncle; co- 

 vering of the eyes convex, prominent, rounded at tip; 

 superior anteiina., a small scale terminating in an acutq 



