Animal having the body flattened, ciliated in front, no cephalic tentacles; eyes sessile. Radula having the formula 1+1+1, the central tooth with a quandrangular base with a large cusp, imbricated, one series on the other ; a lateral transverse plate replaces the lateral and marginal teeth.
Shell planorbiform, spire involute, mouth clasping both sides of the periphery ; operculum corneous, few-whorled, nucleus central.
The animals are very active, and feed on algae.