(MacGillivray, 1827)
Description (shell):
Shell thin, brittle, oblong-oval, umbones just posterior to midline; anterior margin rounded, posterior abruptly truncate. Sculpture of very fine concentric lines, growth stages clear; surface granular, the structure visible with a 10x lens. Chondrophore developed in each valve as a slender, triangular concavity in the hinge line, posterior to the umbo; lithodesma short, peg-like, fitting into a notch in front of the chondrophore in each valve. Adductor scars and pallial line distinct, pallial sinus U-shaped, extending anterio-dorsally to a point just below the chondrophore (T. villosiuscula-drawing).
Size:
Up to 30 mm long.
Colour:
Dull white, periostracum thin, yellowish brown. Inner surface white.
Habitat:
In coarse sand and gravel, from the lower shore to about 60 m.
Distribution:
Reported from various localities in the North Sea, but its distribution elsewhere is uncertain (Distr. T. villosiuscula).