Length 40 mm, height 55 mm, breadth 40 mm. Shell thick, inflated, oval, obliquely towards postero-ventral corner. Beaks prominent, inclined internally. Anterior and ventral margins gently curved but meeting in a blunt angle with posterior margin at the tip of a ridge running from umbo to postero-ventral corner. Region posterior to this ridge rather concave. Surface with 33─36 radial ribs carrying crescent scales, white with irregular brown blotches that become more apparent where scales stripped off. Internal white with strong cardinal plate. Ventral margin crenulated.
Distribution:
North Carolina to Florida, Bermuda and off Suriname. Sublcttoral.