Shell white or cream, large, conical, texture rather thin, very irregularly circular in outline; apex subcentral, slightly curved, inclined anteriorly from apex to posterior end fairly convex; anterior slope either straight or slightly concave. Surface displaying rather strong, irregular, concentric lines of growth crossed by inequidistant radial striae or ridges. Interior white, polished, with a delicate, calcareous half cup-shaped process open on posterior side and extending from the apex into the interior of the shell; margin slightly crenulated. Size: 2 inches.

A most curious shell easily identified by its conical shape and the internal calcareous plate. It adheres to rocks and the under surface of stones partly buried in the sand. The vernacular name of Horse Hoof is sometimes applied to these shells.