86 



whitish, often tinged with red, thick, not polished, with 

 coarse transverse ribs which become warty at the ex- 

 tremities, crossed by indistinct radiating striae, which 

 are usually apparent at the umbones ; anterior slope 

 more or less spotted on one side ; lunule cordiform and 

 wrinkled; inside white. If. English and Irish 

 Coasts. 



P V. CASSINA. Lin. 1130. D. p. 165. Lam. 9. 

 Ch.f. 301,2. Lin. T. 8. p. 79. t. 2. / l.Turt. C. 

 D. p. 232. Da Cos. p. 193. t. 13. /. 4. (left hand) 

 Turt.B. t.9.f.l.p. 141. F. p. 446. Orbicular- 

 heart-shaped, whitish or rusty brown, con vex, with trans- 

 verse smooth plates curving towards the hinge,and nearly 

 meeting each other in an imbricated manner, but not 

 reflected at the sides nor tuberculated ; lunule cordiform. 

 1 . W. and Irish Coasts. 



V. DISCINA. Lam. 6. Philippi. p. 42. Bl. t. 75. 

 f. 6. V. REFLEX A. Mont. Sup. p. 40. and 168. 

 Wern. Soc. 1.^.384. t. 8. /. 1. D.p. \68.-Turt. 

 C. D.p. 233. F.p. 446. Turt. B.p. 142. t. 10. /. 

 1,2. V. RUSTERUCCI. Payraydeau. f. 26, 7, 8. 

 Suborbicular, thickish, rather compressed, a little trun- 

 cated anteriorly, where the transverse plates are thin 

 and reflected, brownish white with usually two or three 



