This species outline does not change very much during the several growth stages, apart some more or less rounded forms (variant orbiculata Wood S.), but it is found a certain variability in the valves convexity (variant crenulata Verril). Also this species, as well as the other ones belonging to the Arcidae family, showes a valves "narrowing" in the anterior zone, clearer near the ventral margin. The sculpture is made by concentric and radial lines forming a fine reticulate. White-yellowish in colour, with a periostracum light brown in colour. The average measures are abt. 4 mm.

Habitat: this species is more common on Brachiopoda bottoms. Distribution: common all over the Mediterranean, always in depth.