3f> 



Lam. 6. Pellucid, fragile, rounded at both ends, hinge 

 margin nearly straight, the ventral slightly curved : 

 a single tooth in one valve and two in the other, besides 

 contiguous lateral processes. ^...1. Sandy Lays. 



S. LEGUMEN. Lin. 1114. D. p. 61. Lam. 11. 

 Ck.f. 32,3, 4 Don. t. 53. Pen. 4. p. 84. t. 46. 

 /. 24. Mont. p. 50. f\ ^, 459. PSAMMOBIA. L. 

 Twr. -B.^3. 90. Linear, rounded at both ends, hinge 

 margin nearly straight, ventral edge slightly curved sx) 

 as to render the posterior end the narrower ; smooth, 

 yellowish, thin, pellucid, with fine lines of growth ; 

 hinge strengthened by an oblique internal rib, a single 

 tooth in one valve and two in the other, besides lateral 

 teeth which are simple in one valve and winged at the 

 other. |... 4. Ireland and Wales, common. 



S. COARCIATUS. Gmel. 3227. D. p. 64. Lam. 



17. Ch. f. 45. S. ANTiQUATUs.iam. 15. Mont. 



p. 52. PSAMMOBIA. A. Turt. B. p. $\.F. 460. 



&. CULTELLUS. Pen. 4. t. 46. f. 25. S. CENTRALIS. 



Say. (fide Jay) . Oblong, rounded at the extremities, 



hinge margin slightly convex, ventral rather concave ; 



white, subpcllucid, merely striated by the lines of 



growth, which are more conspicuous at the extremities; 



