Shell pearly, inequivalve, of various shape according to its environment, attached to some hard substrate by a calcified byssus that passes trough a hole in the right valve. Left valve sligtly convex; right valve following the shape of the substrate.
 

Shell medium-sized, varying greatly in colour; umbo excentred. The left valve bears one large and two small muscle scars.
 

Shell small, whitish, with umbo marginal and pointed; the notch in the right valve is of a reduced size and oval. The genus is monospecific. Two muscle scars in the left valve.
 

Shell small, whitish; the umbo is less marginal than in Heteranomia; the left valve bears two muscle scars.