30 [June, 1841. 



Lima. 



Lima papyria. Obliquely obovate, thin and fragile, inflated ; with 

 prominent radiating lines, distant towards the anterior margin ; 

 anterior margin angulated at base of the ear, truncated or slightly 

 concave below, and abruptly rounded where it joins the basal 

 margin ; ears small. Height 7-8 inch ; length 3-4 inch. 



Arca. 



Area subrostrata. Ovate ; profoundly ventricose ; ribs about 30, 

 little prominent, flat, longitudinally sulcated ; posterior side pro- 

 duced, cuneiform ; rounded at the extremity ; hinge linear in the 

 middle, teeth obsolete, except towards the extremities ; within 

 slightly sulcated ; crenulations of the margin sulcated in the 

 middle. Length 2 inches. 



& 



Pleurotoma. 



Pleurotoma Marylandica. Fusiform, with spiral wrinkled lines ; 

 upper half of whorls of the spine concave, the lower convex, and 

 with oblique ribs. Length 2 1-2 inches. 



P. bellacrenata. Fusiform ; whorls much contracted below the 

 middle, with obsolete spiral lines, and crenate above the suture 

 and on the shoulder of body whirl; body whirl with five or six 

 strong spiral striae, and an intermediate fine line ; back finely 

 striated. Length 11-8 inch. 



Trochus. 



Trochus peralveatus. Volutions 5 or 6, with each a deep groove 

 near the base ; space below the suture profoundly and widely 

 channelled ; upper margin of whirls acutely carinated ; base with 

 5 profound grooves. Length 1 5-8 inch. 



SCALARIA. 



Scalaria pachypleura. Turritted ; shortjin proportion to its width ; 

 volutions 6 or 7, rapidly diminishing in size ; ribs very thick, 

 prominent, reflected, terminating above in prominent angles. 

 Length 5-8 inch. 



