Arca gordita: Acapulco. 20 fathoms (1931). Type 11387, Lowe collection; paratype, Lowe collection, Guaymas, 20 fathoms, (1932).
Shell irregularly ovoid, solid; anterior end roundly sloping downward and backward, posterior end roundly, obliquely produced; color flesh-white; about 27 radiating ribs with somewhat wider interspaces; dorsal margin nearly straight, ventral margin much rounded; greatest altitude of shell in almost vertical line with umbones; anterior wing more sharply produced than the posterior. Diameter 30 mm., altitude 19.1 mm. This shell has about nine less ribs than A. aviculoides Rve., and is a thicker and heavier shell for the same size.