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.
The currently accepted name for this species is Idas simpsoni (J. T. Marshall, 1900).
Key identification features
- The hinge is parallel to the ventral margin of the shell
Ecology and behaviour
Found on the skulls of whales attached by byssus threads in suitable crevices.
Distribution and status
The map provided here shows the distribution of the species based on Conchological Society data.