The map provided here shows the distribution of the species based on Conchological Society data.
Found on the skulls of whales attached by byssus threads in suitable crevices.
- The hinge is parallel to the ventral margin of the shell
Fragile shell up to 2cm in length. It is dirty white in colour but this is obscured by yellow brown periostracum. The inside is pearl white. The surface is sculptured with fine concentric and a few radiating lines.