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. 3%...%. 
Teignmouth, usually dead specimens. 
M. Castanga.—Caprsa C. Turt. B. p. 128. t. 10. 
J. 13.—F. p.434.—Donax C. Mont. p. 573. t. 17. 
S. 2.—Lin. T. 8. p. 77.—D. p. 152.—Turt. C. D. p. 
42.—Oval-oblong, smooth, pale reddish chesnut with a 
deeper longitudinal band from the hinge which curves a 
littie towards the longer side, strong, glossy ; inside 
chesnut. the margin entire, hinge with two teeth (one 
large the other small) in each valve. ¢...2. Penzance. 
Grevvs.— AMPHIDESMA. 
Oval, equivalve, mostly closed, hinge with a spoon- 
shaped tooth, adjacent denticles and lateral teeth : 
ligament external. 
* A. PrismatTicum. Lam. 10.—Turt. B. p. 52. t. 
if. 3.—F. p. 432.—Licura P. Mont. Sup. p. 23. 
t. 26. f.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. 
