128 CALIFORNIA ACADEMY OF SCIENCES. 



Cerritcs,  and i.s iiow in tliu United State.s National Museum. Found also in the 

 Pleistocene of Twenty-sixth Street, Sau Diego. 



Pleistocene. — San Pedro; San Diego (Arnold). 



Superfamily CARDITACEA. 

 Family XIX. CAKDITID.E. 



Genus Venericardia Lamarck. 



Shell siiborbicular, inequilateral, radiately ribbed; hinge widi two oblique cardinal teeth 

 and no laterals. 



Venericardia planicostata Lamarck is a characteristic species. 



54. Venericardia barbarensis Stearns. 



Venericardia barbarensis Stearns, Proc. U. S. Nat. Mus., Vol. XIII , 1891, p. 214, PI. XVI, figs. 3, 4. 



Shell rounded, inequilateral, variable in outline, more or less oblique, moderately convex; 

 beaks small, slightly elevated and turned forward; surface ornamented with nineteen or twenty radi- 

 ating ribs, usually somewhat granulose; lunule small, slightly sunken, faintly defined; hinge-line 

 small, not thick ; hinge composed of, in' left valve, a single strong cardinal sloping posteriorly 

 and a smaller tooth, often obscure, slanting anteriorly; a third tooth-like process is generally present, 

 situated under, and apparently a projection of, the edge of the lunule; the right valve has a single 

 strong cardinal tooth with a slanting, somewhat sinuous groove above and a slight notch and tooth- 

 like point below the upper part of the lunule; muscle impressions small. 



Diiuensiofis. — Long. 19.5 mm.; alt. 17 mm.; diam. 14 mm. 



Distinguishable from I', ventricosa by more subrectangular outline, greater 

 relative length; greater number of ribs, less prominent beak, much narrower and 

 longer hinge-line, and shorter, slighter posterior cardinal tooth, which is straight. 



Common in Pliocene and lower San Pedro series of Deadman Island; rare 

 in Pliocene at Timm's Point and upper San Pedro series of Crawfish George's and 

 San Pedro. Found also west of bath-house at Santa Barbara. 



Living. — Santa Barbara Islands (276 fathoms) (Stearns). 



Pleistocene. — San Pedro (Arnold): Santa Barbara (Arnold). 



Pliocene. — San Pedro (Arnold). 



55. Venericardia venti-icosa Gim/d. 



Cardila ventricosa Gi^u., Proc. Bost. Soc. Nat. Hist., 1850, p. 276; Wilkes Hxpl. E.x[)ed., Vol. XII, 



p. 417, PI. XXXVI, fig. 532, 1852, =C. subte7ita Con., =C. monilicosta Gabb, ^C. occi- 



dentalis Con., {fide Gabb, Pal. Cal., Vol. II, 1869, p. 100). 

 Venericardia borealis \-3S . ventricosa Gld., Cpr., Brit. Assn. Rept., iS63,ix 643, Cooper, 7th Ann. 



Rept. Cal. St. Min., 1888, p. 269. 

 Veiiericardia veyitricosa Gld., Stearns, Proc. U. S. Nat. Mus., Vol. XIII, 1891, p. 216, PI. XVI, 



figs. 5 and C. W1LLIAM.S0N, Proc. U. S. Nat. Mus., Vol. XV, 1892, p. 190. 



