(Müller O.F., 1776)
Description (shell):
Shell thin and brittle, elongate-oval, umbones just posterior to midline; anterior and posterior hinge line sloping equally from umbones. Sculpture of very fine concentric lines, scarcely visible with hand lens; growth stages unclear. Chondrophore slender, posteriorly directed. Right valve with two short cardinal teeth anterior to chondrophore and single, elongate, anterior and posterior laterals; left valve with one cardinal tooth and poorly developed, single anterior and posterior laterals. Adductor scars and pallial line visible with hand lens, cruciform muscle scars indistinct. Pallial sinus deep, lower edge partly confluent with pallial line (A. nitida-drawing).
Size:
Up to 12 mm.
Colour:
Outer and inner surfaces white, glossy.
Animal:
Clear white, with a large foot and two very long siphons; the mantle is fringed with short cilia.
Habitat:
Burrowing in mixed soft substrata, offshore to the edge of the continental shelf.
Distribution:
Widespread, and often common (Distr. A. nitida). Distributed from Norway south to the Mediterranean and north-west Africa.