A shell or an operculum, may be spiral, without being produced into a pyramid.
The outer lip is also thickened and bent inward, and there is no operculum.
These fishes generally have an air-bladder, and the gills lie close together in a cavity covered by an operculum.
In Cryptohelia the cyclosystem is covered by a cap or operculum.
Seed large; the apex or radicular extremity of the seed-coat separable as an operculum or lid (as in Cabomba, etc.).
This flap, an outgrowth of the hyoid arch, is known as the operculum.
The capsule opens explosively in dry weather, the operculum and spores being thrown to a distance.
Their gill-clefts are covered by an operculum, and they have a well-developed air-bladder.
One I found on the bushes with an operculum--this I gave to Wall.
There is no operculum and no representative of the maxilla or premaxillae.
operculum o·per·cu·lum (ō-pûr'kyə-ləm)
n. pl. o·per·cu·lums or o·per·cu·la (-lə)
Something resembling a lid or cover.
The portions of the frontal, parietal, and temporal lobes covering the insula.
The mucus sealing the endocervical canal of the uterus after conception.
The attached flap in cases of torn retinal detachment.
The mucosal flap partially or completely covering an unerupted tooth.