pholas

[Gr. phōlas =a moilusk which makes holes in stones; Litho dom us (?).] Zool. & Palæont .: Piddock; the typical genus of the Pholadide (q. v.). Shell long, cylindrical, acce ory valves protecting the dorsal margin. Animal with a large, truncated foot, body with a fan-like termination. They live in symmetrical vertical burrows. Recent species thirty-two, from most seas; fo il twenty-five, from the Upper Lias onward.