Shell small to medium, up to ~85 mm. Outline
irregularly subcircular. Right valve usually more convex than
the left. Rounded radial ribs may be present on both valves
and ending at rounded and plicate ventral margins. Shell
exterior usually smooth with a waxy texture and covered by
occasional and weak growth squamae. Shell interior us white with brown or light green patches. Chomata along margins
restricted near hinge or extended to the ventral margin.
Larviparous.