Hiatella arctica (Linnaeus, 1767)
Up to 15-20 mm.
Dull white; periostracum coarse, yellow-brown. Inner surfaces white.
Attaches by a byssus, in holes, crevices, or algal holdfasts. The adults are able to bore into rock by mechanical abrasion using the valves of the shell.
Found on the lower shore and down to about 50 m in depth.
Arctic waters and south.