The ovate shell is oblong, transverse, with unequal valves. The beaks are strongly recurved, that of the right valve notched to receive that of the opposite side. The right valve is more convex and larger than the left. The hinge has upon each valve a horizontal and narrow nympheal callosity, which sometimes expands into a spoon-shaped projection, and contains an internal ligament, which is prolonged, and slightly issues outwardly into the corselet. The shell shows two muscular impressions, the anterior depressed, elongated, contracted towards its middle, and united to the posterior, which is rounded, by a pallial impression, strongly notched at its posterior part.Kiener (1840). General species and iconography of recent shells : comprising the Massena Museum, the collection of Lamarck, the collection of the Museum of Natural History, and the recent discoveries of travellers; Boston :W.D. Ticknor,1837
