forating tooth in each valve, lateral teeth none : 



ligament external. 



A. PURPUREA. Turt. B. p. 54. t. 4. /. 9. MYA. 

 P. Mont. Sup. p. 21. SOLEN P. F. p. 459. Oval, 

 obliquely truncated anteriorly, convex, opaque, under 

 a glossy white cuticle, chalky white, with irregular con- 

 centric striae ; inside glossy white, hinge with a single 

 ronic tooth in each valve penetrating a corresponding 

 ca'ity in the opposite. i...i. Torbay, in rocks. 



GENUS. VENERUPIS. 



Transverse, inequilateral, posterior side short, the an* 

 terior slightly gaping ; hinge with two cardinal teeth 

 in the right value and three in the left (sometimes 

 three in each) ; teeth small approximated, parallel 

 and slightly divergent : ligament external. 

 V. IRUS. Lam. 3 F. p. 451 DONAX I. Lin. 

 1129. D.p. 156. CA./. 268,9. Pen. 4. p. 100. 

 Mont. p. 108. and 573 .-Don. 1. t. 29. f. 2.Lin.T. 

 S. p. 77. Dor. Cat. p. 34. t. 12. / 6. (left-hand.) 

 Turt. C. D. p. 43. Da. Cost. p. 204. t. 15. /. 6. 

 (left-hand) PETKICOLA I. Turt.B, p. 26. t. 2. /. 

 14. Oblong or oval, but variable in modifications 

 being at times truncated and sometimes rounded, dull 

 dirty white, with rather distant, thin, transverse, sub- 

 reflected lamellae and regular close radiating striae in 



