Turton, 1822
Description (shell):
Shell thin and fragile, irregularly oval, umbones anterior to midline; anterior end rounded, posterior sloping away from umbones, somewhat attenuated, irregularly rounded or gently truncate. Sculpture of fine concentric lines, growth stages clear. Left valve with a short, broad chondrophore projecting horizontally from beneath umbo, continuous posteriorly with the thickened dorsal margin. Left valve with a recessed chondrophore, completely obscured beneath umbo. Adductor scars and pallial line distinct; anterior scar elongate, posterior rounded (S. binghami-drawing).
Size:
Up to 20 mm.
Colour:
White, with pale green or brown periostracum.
Animal:
The siphons are short, especially the incurrent one. This species does not burrow in the ground as its congeners do (S. binghami-animal).
Habitat:
Attaches by a byssus, in holes and crevices or algal holdfasts, in shallow sublittoral waters.
Distribution:
Distributed southwards to the Mediterranean and north-west Africa (Distr. S. binghami).