Circular to oval, free upper right valve flat, lower attached left valve deeply cupped, margins rising vertically from substratum, inflated, thin-walled, white to pink to orange, surface relatively smooth with few indistinct plications on left valve; interior surface dull. North Carolina to Florida, Bermuda, West Indies, also western Europe and Indo-Pacific from Red Sea, Madagascar, Philippines, Japan, and Hawaii. Length 13 mm (to 7 cm). Note: This species lives at greater depths than any other Recent oyster.