(Linné, 1758)
Description (shell):
Shell thick and strong, subtriangular, anterior more regularly convex than posterior but not markedly so; umbones more or less on midline, anterior and posterior hinge with approximately equal slope. Sculpture of fine concentric lines, developed as fine ridges in front of and behind umbones; growth stages distinct. Lunule and escutcheon poorly defined. Right valve with two short cardinal teeth and paired, elongate anterior and posterior laterals. Left valve with three cardinal teeth; anterior two forming a forked structure which extends only halfway down hinge plate, third very small; single, elongate anterior and posterior laterals. Interlocking surfaces of lateral teeth serrated. Chondrophore posterior to cardinal teeth. Adductor scars and pallial line distinct, pallial sinus linguiform, extending to a point below and beyond the midline of the posterior laterals (S. solida-drawing).
Size:
Up to 50 mm long.
Colour:
Dull white to light fawn; periostracum greyish brown, usually prominent around margin and along growth lines. Inner surfaces glossy, white.
Animal:
The animal has a thick mantle with fringed edges. The siphons are short, their mouths fringed with yellow or red filaments; united throughout their length, but the exhalent tube is fitted with a tubular valve. The foot is large, tongue shaped and very extensible, used for burrowing and leaping . Colour white or yellow tinged with brown. (S. solida-animal).
Habitat:
Burrows in sand, from the lower shore down.
Distribution:
Distributed from south Iceland and Norway to Spain and Morocco (Distr. S. solida).