Definition:
The operculum in fish is a bony gill cover; comprised of four bones: opercle, preopercle, interopercle and subopercle. In snails and some annelids, it is a calcified or proteinaceous plate used to cover the opening of the shell when the animal is withdrawn inside.
The operculum in fish is a bony gill cover; comprised of four bones: opercle, preopercle, interopercle and subopercle. In snails and some annelids, it is a calcified or proteinaceous plate used to cover the opening of the shell when the animal is withdrawn inside.
