Subfamily Lithophaginae H. Adams & A. Adams, 1857

More or less elongate, cylindrical, beaks slightly behind anterior end, hinge margins generally smooth, periostracum commonly with calcareous incrustations (Soot-Ryen 1969). Hinge edentulous, extensible siphons relatively long. Ventral edges of incurrent or branchial siphon touch to form a tube, excurrent or anal siphon complete.