« A very light brittle shell, remarkably convex, and strongly angulated at the anterior end. The outside is concentrically striated, and covered with an ochreous coat, rather rough near the anterior edge ; when deprived of this coat, the shell is perfectly white. Inside yellowish white ; tooth small, oval, and projecting horizontally. This species is certainly distinct from the following [Mya declivis p. 93 – junior syn. of M. arenaria p. 90], which is a much stronger and flatter shell. Its remarkable convexity has induced the author to give it the trivial name of convex gaper. Donovan has evidently figured this shell, under the name of M. declivis. »