428 CRUSTACEA [November 



ly in rivulets under stones. It is frequently introduced with 

 the Schuylkill water into Philadelphia. The female may 

 be distinguished from the male by a valvular pectoral fol- 

 licle in which the young are protected. . In one of these 

 I counted twenty- eight young ones. 



2. A. lineatus'^. Body oblong; interior antenna much 

 shorter than the peduncle of the exteriores; caudal appen* 

 dices, peduncle cylindrical. 



Inhabits South Carolina. 



Cabinet of the Academy. 



Body oblong, not distinctly attenuated before; seg' 

 ments subequal, entire; head at base equal to the prece- 

 ding segment, a sinus each side in the middle; eyes pro- 

 minent, black; antenna, exteriores as long as the body 

 in one sex, in the other longer, interiores nearly attaining 

 the tip of the second joint; hands with a prominent angle 

 on the middle of the inferior edge, thumb closing on and 

 surpassing the angle, shorter than the hand; nails some- 

 what bifid at tip; terminal caudal segment longitudinally 

 subovate, styles elongated cylindrical, equal to the termi- 

 nal segment of the body, lacinige very unequal, inner one 

 nearly thrice the length of the outer one, truncate at tip; 

 colour pale brown with a double dorsal brown line, united 

 at the tip of the tail, a brown line or two each side of the 

 t»il. 



Length nearly one fourth of an inch. 



This animal is not an uncommon inhabitant of the 

 swamps in the forests of South Carolina. It might be re- 

 ferred to the genus Janira of Dr. Leach, 



