Shell aragonitic, homogeneous or crossed-lamellar; interior porcclancous, rarely subnacreous. Subequilateral to inequilateral, inflated, venerid shaped. Periostracum thin, dull, adherent. Sculpture commarginal. Anterior and posterior gapes absent. Hinge plate with taxodont teeth in two series, sometimes separated by narrow plain area, without resilifer. Ligament external, opisthodetic to amphidetie, weak. Pallial sinus large. Foot with papillated, planar sole. Siphons present, inhalant and exhalant fused. Hypobranchial glands absent. Gills protobranch, with many plates. Labial palps large, with many ridges; palp proboscides narrow, long. Alimentary canal with type 1 stomach; three ducts leading to digestive diverticula; style sac not fused to mid-gut; intestine passing through ventricle of heart.
The family may be related to the Nuculanidae, but the lack of a resilifer supports its separation. They differ from the Malletiidae in being smaller and in lacking conspicuous gapes, and from Tindariidae in having siphons and a short gap in the dentition under the beaks (except in Austrotindaria). There are three living genera with approximately 35 species. Known from the Jurassic and present in all oceans, especially in deep water in soft substrata.