Teeth (dental plate) straight; crown enlarged and flat with a hexagonal contour in the occlusal face. Lingual face with a central depression between the crown and the root.

Size: 3-30 mm (length).

Ecology: inhabits nearshore-shallow waters, feeding on clams, oysters, and other invertebrates, which it draws into its mouth using suction and crushes with its dental plate; known to grow to 80-90 cm in length.

Geological range: Cretaceous-Recent.

Geographic distribution: Pacific in the present day.