818.] CRUSTACEA, Sec. 423 



An account of the Crustacea of the United States. By 

 Thomas Say, Read September 22, 1818. 



(Conclud* d ) 



G^ww5 STENOSOMA. Leach. 



Body sublinear; tail two or three jointed, ultimate 

 joint destitute of lateral appendices, furnished beneath 

 with two parallel laminae, attached by their external mar- 

 gins and opening like valves; antenna^ exteriores elonga- 

 ted, interiores very short. 



SPECIES 



1. S. irrornta*. Body oblong, third segment broadest, 

 attenuated to the tip of the tail, which is three toothed, 

 middle tooth longest. 



Inhabits Egg-harbour; common. 



Cabinet of the Academy. 



Body oblong, attenuated before and behind from the 

 third segment, second, third and fourth segments longest, 

 nearly equal; tail with, the first and second segments equal, 

 short, third equal on each side to the preceding, but ob- 

 solete above, terminal segment as long as the six preced- 

 ing ones conjunctly, longitudinally somewhat elevated on 

 the disk, tip with two crenas forming obtuse lateral teetli 

 and a more prominent middle one; antenna half as long 

 as the body, interior ones very short, attaining the tip of 

 the third joint of the exteriores; eyes somewhat hemis- 

 pherical, placed on the middle of the lateral margin. 



Length, female rather more than one half of an inch. 



Very common in bays and inlets of the coast on 

 fuci, &c. 



