(Pulteney, 1799)
Description (shell):
Shell thin and brittle, oval, umbones just posterior to midline; anterior margin rounded, posterior somewhat truncate, directed ventrally; with a small posterior gape. The hinge line posterior to umbones is sloping gently . Sculpture of fine concentric lines, growth stages discernible with hand lens; on each valve a distinct crack extends for a short distance posteriorly from the umbones - a lens is necessary for small specimens. Posterio-dorsal surface of shell finely granular, with coarser periostracum, and often encrusted detritus. Chondrophore elliptical, projecting, arising posterior to the umbone and directed obliquely anteriorly. Adductor scars and pallial line clear, pallial sinus regular, U-shaped, extending almost as far as the chondrophore (C. pratenue-drawing).
Size:
Up to 40 mm long.
Colour:
Dull white, periostracum light yellowish brown. Inner surfaces white.
Animal:
The animal, including the tongue-shaped foot, is white. The shells gape behind to allow the continuous extrusion of the long separate siphons.
Habitat:
In mixed fine deposits, from the lower shore to about 100 m.
Distribution:
Distributed from Norway and southern Iceland to the Mediterranean (Distr. C. praetenue).