noun, plural o·per·cu·la [oh-pur-kyuh-luh] /oʊˈpɜr kyə lə/, o·per·cu·lums.
- the gill cover of fishes and amphibians.
- (in many gastropods) a horny plate that closes the opening of the shell when the animal is retracted.
Origin of operculum
Related formso·per·cu·lar, adjective
Examples from the Web for opercular
The embryo leaves its shell by the opercular aperture, and for some time swims rapidly about by means of its long cilia.
In Spirorbis Pagenstecheri they develop inside the opercular tentacle, and in Spirorbis spirillum inside the tube of the parent.
The al are added to above the level of the opercular membrane.
It may here be mentioned that on the opercular membrane many long spines stand rudely arranged in rows.
Parietal valves six; opercular valves four, placed against each other conically in pairs.A Conchological Manual|George Brettingham Sowerby
British Dictionary definitions for opercular
noun plural -la (-lə) or -lums
- the hard bony flap covering the gill slits in fishes
- the bony plate in certain gastropods covering the opening of the shell when the body is withdrawn