Really variable species in its form and in its sculpture. It reaches bigger sizes than Chama gryphoides but. above all, it is different for the sinistrorsc character of the umbo (opposite to gryphoides one) and for the valves sculpture made by lamellae squamosum concentric more or less developed, instead of gryphoides little tubercles and small lamellae. The average measures can reach 35-40 mm in diametre. Dirty white or yellowish in colour, sometimes with rosy shades.

Habitat: it lives in the infralittoral plain fixed to solid substrata of several kinds. Distribution: common all over the Mediterranean. It seems to be missing in the Black Sea.