54 



obtuse, smooth, variable in color, being sometimes uni- 

 form yellow, pale with three or four chesnut or dark 

 rays and often yellow with a broad central white 

 ray edged with chesnut; inside yellowish. i...f. 

 Teignmouth, usually dead specimens. 



M. CASTANEA. CAPSA C. Turt. B. p. 128. t. 10. 

 /. 13. .F.^.434. DONAX C. Mont. p. 573. t. 17. 

 /. 2. Lin. T. S.p. 77. D. p. \52.-Turt. C. D. p. 

 42. Oval-oblong, smooth, pale reddish chesnut with a 

 deeper longitudinal band from the hinge which curves a 

 little towards the longer side, strong, glossy ; inside 

 chesnut the margin entire, hinge with two teeth (one 

 large the other small) in each valve. .... Penzance. 



GENUS. AMPHIDESMA. 



Oval, equivalve, mostly closed, hinge with a spoon- 

 shaped tooth, adjacent denticles and lateral teeth : 

 ligament external. 

 * A. PRISMATICUM. Lam. 10. Turt. B. p. 52. t. 



5.f. 3.F. p. 432. LIGULA P. Mont. Sup. p. 23. 



t. 26./.3. Pen. 4.p. 169. MYA P. Wood. G. C. 



p. 101. D. p. 47 Turt. C. D. p. 103. Oblong, 



* In British Species, the lateral teeth are only in one 

 valve. 



