430 CRUSTACEA fNovcmbcr, 



segments somewhat glabrous, terminal segment surpass- 

 ing the first joint of the lateral styles; antennae rough and 

 . subspinose before, terminal joint glabrous, pale; feet be-^ 

 neath armed with short distant setae. 



Length nearly one- fifth of a$i inch. 



Under stones, old wood, &.c. in moist situations neai' 

 Savannah^ Georgia. 



Genus ONISCUS. 



Caudal styles four, lateral ones biarticulate, interme- 

 diate ones concealed by the terminal segment of the tail; 

 antennae, exteriores eight-jointed, interiores obsolete; tail 

 not abruptly narrower than the body. 



SPECIES. 



O. affinis^. Head and anterior segments of the body 

 scabrous; tail glabrous, terminal segment attenuated, at- 

 taining the tip of the inferior styles, and the middle of 

 the last joint of the exterior ones. 



Inhabits North America; common. 



Cabinet of the Academy. 



Body dilated, oval, somewhat depressed, sides a little 

 rounded, not rectilinear;, head and anterior segments of 

 the body scabrous, posterior segments gradually less so; 

 tail glabrous; terminal segment, almost subulate, attain- 

 ing the middle of the last joint of the exterior styles, 

 and exactly equal to the interior ones; colour fuscous 

 with a cinereous edge and submarginal line, which are 

 united on the tail into a broad margin, disk with a few 

 cinereous spots. 



Length half an inch, breadth three tenths of an inch. 



Inhabits damp places, under stones, decaying wood. 



