Murex Opercula

Most univalves (single-shelled snails) have a little ‘door’ called an operculum, made of a horny substance and attached to the snail’s foot. When the snail retreats into its shell, this little door shuts neatly behind it, sealing the opening with the animal safely inside. Pictured are two fine, brittle opercula from murex shells. Photograph © James Prineas, 2003