Shell inequilateral, sub-orbicular, close, equivalve, sometimes attenuated at one end; two divergent primary teeth, with a cavity at the side; lateral teeth obsolete; ligament internal, inserted in the cavity of the hinge.

Crassatella Kingicola.

C. donacina.

C. sulcata.

C. subradiata.

C. contraria.

C. cuneata.

C. rostrata.

C. glabrata.

C. erycinæa.