Chlamys varia

(Linné, 1758)

Description (shell):
Shell thin, more or less oval. Inequivalve: right valve with a distinct, rounded byssal notch in anterior ear, with fine teeth on lower border. Inequilateral: both valves with anterior ear more pronounced, twice as long as posterior. Sculpture of 25-35 bold ribs, and a few corrugated concentric lines, raised into prominent spatulate spines along ribs, most pronounced close to margin. Ears similarly ribbed. Growth stages usually clear (C. varia-drawing 2). Sculpture visible on inner surface, margin crenulate .

Up to 60 mm long.

Colour very variable, from off-white, through yellow and orange to brick-red, purple, or brown, often with bands or patches of darker or lighter colour. Very young stages usually unicolorous. Inner surface of shell glossy, often coloured same as exterior (C. varia-drawing).

Attached by byssus when young, but may become free later. Mantle with a double margin, the inner finely fringed and the outer edged with long tentacles. About 30 eye-spots at the base of the tentacles.

From lower shore to about 100 m. Often grows enclosed by algal holdfasts.

Widespread and common in the North Sea (Distr. C. varia). Present in the Mediterranean, distributed south to west Africa.