The family is monogeneric. See description below.
 

Shell inequivalve, inequilateral, often heavy. Upper valve with auricles, radially ribbed and striated; the ribs adorned with spines more or less spatulate. Lower valve attached anteriorly to hard substratum, and often adorned with foliations arranged more or less concentrically. Hinge with two large teeth on each side. Margins internally crenulate and often deeply coloured.