The deck is usually concave and white to buff. Its edge is strongly sinuate or waved in two places. Exterior dirty-white to tan, sometimes with brownish blotches and rarely with long color arched. They may be corrugated if the individual has lived attached to a scallop or ribbed mussel. A common littoral species.
Individuals usually stack up on top of one another.
The lateral teeth bear very tiny, sawtooth ridges. Color yellowish white with a thin yellowish brown periostracum. Common below low-water mark on ocean beaches. Sometimes cast ashore on South Carolina beaches. One and one-half to 3 inches in length, obliquely oval with a long extension of the hinge line toward the posterior end.