Obliquely oval, umbones slightly anterior of center, inflated, solid, white with thick black-brown periostracum, with 26-35 smooth radial ribs, no byssal gape; interior white, margin coarsely den-ticulate, cardinal area narrow, hinge line arched, teeth more numerous posteriorly, those near umbones coarse. Massachusetts to Florida, West Indies, Gulf of Mexico, Caribbean Central America, South America (to Uruguay). Length 40 mm (to 56 mm). Formerly in Anadara.