Atlantic deep sea scallop

Marine bivalve mollusc. The shell is large, subcircular, and compressed. The two valves are subequal. The right valve rests on the bottom. Radial ribs are present along with concentric lamellae or growth lines. This sculpturing is more prominent on the left valve. The wings on the left valve are nearly equal: the wings on the right valve differ in that the anterior wing contains a byssal notch. The inner surface is lustrous and smooth with distinct adductor muscle and pallial scars. The adductor muscle scar is located slightly posterior and dorsal to the center of the valves and is slightly larger on the left valve. The left valve is usually reddish-brown in color but may be lavender or yellow; the right valve is pale cream or white.