CLASS PELECYPODA 
147 
Type locality, Straits of Georgia, between Race Island, and Lighthouse 
and Victoria Harbor, British Columbia. 
Range. Queen Charlotte Islands, British Columbia, to San Francisco, 
California. 
Family VESICOMYACID.7E. 
Genus VESICOMYA Dali, 1886. 
Shell small, smooth or concentrically striate; hinge of Meiocardia but 
without lateral teeth; epidermis polished, umbones moderately prominent; 
lunule circumscribed by a groove; otherwise as in Meiocardia. (Dali.) 
Type. Callocardia atlantica Smith. 
Distribution. West coast of North America. 
Vesicomya lepta Dali, 1896. 
Proc. U. S. N. M., 18:17. Bull. Comp. Zool. } 43; pi. 18, figs. 12, 14. 
Shell large thin, earthy, white, compressed, with an olivaceous or 
yellowish, dehiscent epidermis, with concentric wrinkles and projecting 
laminae, which in the young are somewhat regularly spaced and distant, 
in the adult crowded and irregular; beaks small, low, not conspicuous, 
moderately inflated; valves evenly arcuate below, rounded at both ex¬ 
tremities, the anterior shorter and less high than the posterior; lunule 
narrow, long, bounded by an incised line; ligament external, long, set 
in a groove, with the escutcheon narrow, its edges elevated above the 
dorsal margin of the valves and obtusely keeled, extending one-half longer 
backward than the length of the ligament; interior smooth, or slightly 
radially striate, margins flattish, smooth; anterior adductor scar narrow, 
posterior wider, the pallial line joining it in front of its posterior edge, 
producing an indentation, though not a sinus, of the pallial line; hinge 
narrow; teeth small, compressed, three (more or less obscure) in each 
valve; in the right a long, strong anterior lamella, extending most of the 
way between the umbo and the adductor scar, with a socket around its 
posterior end, above this a short, small, thin, lamina, joined around the 
socket with a thicker lamina, obscurely wavy and extending backward; 
in the left valve a stout subtriangular central, joined to a thin, short, 
anterior lamina, with a socket under it; a short, obscure, radial tooth 
behind the central one; no lateral teeth in either valve, and the cardinals, 
as usual in this group, somewhat variable, obscure or ill-defined. Length, 
53; height, 40; diameter, 23 mm. (Dali.) 
Type in U. S. N. M., No. 126751. Type locality, Station 3009, in the 
Gulf of California. 
Range. Off Tillamook, Oregon, to the Gulf of California. 
