CLASS PELECYPODA 
151 
Amiantis callosa Conrad, 1837. 
Plate 56, figs. 1, 2. 
Jour. Acad. Nat. Sci. f 7 :252. Thes. Conch. Venus; pi. 114, figs. 44, 45. 
Shell subovate, convex-depressed, white; valves with numerous con¬ 
centric flattened ribs, some of which are divided or interrupted on the 
anterior and posterior sides; valves irregularly thickened in the interior, 
except near the margins; pallial impression very distinct, and the sinus 
profound. Length, 2 inches. (Conrad.) 
Type locality, near Santa Barbara, California. 
Range. San Pedro, California, to the Gulf of Tehuantepec, Mexico. 
In the Pleistocene at San Pedro and San Diego, California. 
Genus PITARIA Roemer, 1857. 
Shell trigonal, plump, concentrically striate or rippled, with an incon¬ 
spicuous periostracum and delicate coloration; lunule circumscribed, but 
the escutcheon not defined; inner margins smooth, pallial sinus ample, 
elongate, somewhat ascending, pointed in front; middle cardinal stout, 
the others slender; the posterior cardinals feebly grooved, the others 
entire; the cardinals of the right valve discontinuous where they touch the 
dorsal margin and not separated from the latter by a groove; anterior 
lateral adjacent, distinct; nymphs and teeth smooth; dorsal margins 
grooved as in Meretrix. 
Type. Ve?ms tumens Gmelin. 
Distribution. Widely distributed in the tropics. 
Pitaria newcombiana Gabb, 1865. 
Plate 57, fig. 2. 
Proc. Cal. Acad. Set., 3:189. Proc. U . N. M., 15; pi. 23, fig. 4. 
Shell thin, trigonally ventricose, polished, marked by minute concen¬ 
tric strise; beaks large, subcentral; anterior end prominent, narrowly 
rounded, posterior a little the widest, base convex; lunule not excavated, 
bounded by an impressed line; color yellowish white, variously lined with 
brown angular lines; interior whitish; internal margin smooth; hinge 
teeth delicate. (Gabb.) 
Type in Mollusca, Survey Cabinet (of California), No. 1058. Type 
locality, Catalina Island, California, in 120 fathoms. 
Range. Monterey, California, to Lower California. In the Pleis¬ 
tocene at San Pedro and San Diego and the Pliocene at San Diego Well, 
California. 
Genus ANTIGONA Schumacher, 1817. 
Shell thick, ovate, smooth, sulcated, or cancellated; margins minutely 
crenulated; cardinal teeth 3—3; pallial sinus small, angular; ligament 
prominent; lunule distinct. (Tryon. S. S. Conch.) 
