Iceland & Norway to Angola, Mediterranean. Lives offshore, attached to stones, debris and other shells. Suspension feeder. Original taxon: Anomia patelliformis. Synonyms: elegans, pectiniformis, undulata… Left valve radially striated.

« Shell round or sometimes longitudinally oval, usually flattened, thin, rather glossy towards the beak, but elsewhere of a dull appearance. Sculpture, fine and close-set imbricated scales, and 20-30 blunt ribs which radiate from the beak in every direction towards the margins in a wavy manner ; lines of growth irregular. Colour yellowish-white, with frequently reddish-brown but not continuous streaks or spots. Margins thin, scalloped or notched by the ribs, nearly straight behind. Beak small, rather prominent, very seldom reaching to the hind margin, and never overlapping it. » – J. G. Jeffreys: British conchology vol. V, via BHL.