202 
MARINE SHELLS OF WEST COAST OF NORTH AMERICA 
Genus PLATYODON Conrad, 1837. 
Shell resembling the type Myce, but with a less prominent and more 
dilated tooth; pallial impression slightly sinuous anteriorly; posterior 
sinus profound. 
Type. Platyodon cancellatus Conrad. 
Distribution. California. 
Platyodon cancellatus Conrad, 1837. 
Plate 32, figs. 2a, 2b. 
Jour. Acad. Nat. Sci. Phita., 7:236; pi. 18, fig. 2. 
Shell sub-elliptical, ventricose, with numerous prominent, slightly 
undulated, concentric striae; a slight furrow extends from beak to base; 
posterior side with radiating striae; obsolete or wanting on the posterior 
slope; umbo prominent; posterior side short; cardinal tooth very erect, 
dilated, bi-marginate. Length, 3 inches. (Conrad.) 
Type locality, near Santa Barbara, California. 
Range. Bolinas Bay to San Diego, California. In the Pleistocene 
at San Pedro, California. 
Family CORBULID.®. 
Genus CORBULA Brugiere, 1792. 
Shell thick, inequivalve, gibbous, closed, produced posteriorly; right 
valve with a prominent tooth in front of the cartilage pit; left valve 
smaller, with a projecting cartilage process; pallial sinus slight; pedal 
scars distinct from the adductor impression. (Tryon. S. S. Conch.) 
Type. Corbula sulcata Brugi&re. 
Distribution. United States, Norway, Britain, Mediterranean, West 
Africa, China. Inhabits sandy bottoms. 
Range in time. Inferior Oolite. United States, Europe, India. 
Corbula obesa Hinds, 1843. 
Proc . Zool. Soc., 1843, p. 57. Zool. Sulphur Voy., Moll ., pi. 20, fig. 12. 
Shell ovate, thin, ventricose, pale, striated, posteriorly rounded, an¬ 
teriorly truncated at the end, sharply angulated from the umbos; ventral 
margins of the valves closed in, gibbous; umbos smooth, straight. (Hinds.) 
Type in Museum Belcher. Type locality, West Coast of America. 
Range. Catalina Island, California, to Panama. 
