The fold of integument, usually supported by bony plates, which protects the gills of most fishes and some amphibians; the gill cover; the gill lid.

The principal opercular bone in the upper and posterior part of the gill cover.

The lid closing the aperture of various species of shells, as the common whelk. See Illust. of Gastropoda.

Any lid-shaped structure closing the aperture of a tube or shell.

This is a bony plate that covers the gills.

Bony covering over the gill slits of fish; or, in gastropod molluscs, the calcareous plate over the shell opening that protects the body when the animal withdraws into the shell.

lid of a pyxidium ( q.v.)

A covering/forming a covering. For female Janiroidean asellotan isopods the operculum equates to a plate over the branchial chamber of the abdomen consisting of the fused second pleopods (the first pleopods are absent in these isopods).

a horny plate that seals the opening of the shell, this is absent in adult nudibranchs, but present in the larval stage

A thick membrane covering a porus or colpi. Half the operculum can be lost because there tends to be a very thin area just inside the immediate margin of the aperture.

A large flap consisting of several flat bones located on the side of the head and covering the gill chamber.

a plate serving t close the aperture when the animal retreats into its shell. Present in a few primitive opisthobranchs. Lost in adult nudibranchs.

lid on a sporangium that, when popped off, or hinged open as here, allows the zoospores to escape. Sporangia that have this type of release mechanism are said to be operculate.

The lid which closes the capsule and permits the spores to escape when it falls.

horny or calcareous plate (or plates) covering the main opening or aperture of the shell, as in barnacles and certain gastropods.

The hard plate covering the soft fleshy gills.

Latin = lid or cover; hence, operculum insulae, the cerebral cortex covering and hiding the insula (the 5th lobe of cerebral cortex).

Operculum - The opening of a shell.

bony plate covering the gill cavity in the head of a fish. Gill slit runs along the posterior edge of the operculum.

The lid or cover-like specialisation of a parasite eggshell through which the larva escapes.

A thicker central part of a pore membrane of a pollen grain ( Plate 23: 380).

cartilaginous covering which protects the gills of fish.

The lid, horny or calcareous, which closes the aperture when the head and foot are withdrawn into the shell.

the bony covering of the gill cavity composed of opercular bones

a hard flap serving as a cover for (a) the gill slits in fishes or (b) the opening of the shell in certain gastropods when the body is retracted

Small disk-like cover or lid of an aperture, commonly found in cheilostomes.

A generally uncalcified lamina (or flap), hinged, or pivoting on condyles, which closes the zooidal orifice in Cheilostomata (Hayward & Ryland, 1979). Calcified opercula are found in some cheilostomes, and also in the cyclostome Family Eleidae .

A bony flap covering the gills of fish.

o-PER-cu-lum A flap of tissue that protects gills. 734

(1) the lid of a moss capsule. (2) the hard bony flap covering the gills of fishes. (3) the plate of exoskeletal material on the foot of a gastropod mollusk with which it closes off the entrance to the shell.

Hard cover protecting gills

That part of the cortex, chiefly of the parietal lobe, which overhangs the insula. The operculum properly includes also a part of the temporal and the frontal lobes.

A hard, bony plate which covers the gills.

(L. cover or lid): Adjoining parts of the frontal, parietal and temporal lobes which overhang and conceal the insula from view.

the gill-cover of a fish; the plate which closes the shell aperture of sorne molluscs.

A lid or covering flap found in several different groups of invertebrates. Most often used to cover an opening in the animal's exoskeleton.

Bony gill cover; comprised of four bones: opercle, preopercle, interopercle and subopercle. ( 126) See chart for details.

a lid or covering that closes the shell opening in snails, or the bony gill covering of a fish.

gill covers.

In gastropods, this is a trapdoor or lid to seal the opening in the shell to protect their soft bodies from predators and drying out. The trapdoor is usually attached to the gastropod's foot. On the right is a series of diagrams showing how a snail uses its operculum to seal the shell opening.

Lid or cap--like structure at one or both ends of certain worm eggs, i.e., Trichuris and fluke; the larval parasite emerges from the egg at the operculum.

The flap of tissue over an unerupted or partially erupted tooth.

a small round lid.

Shiny bone covering gill opening; also called gill cover.

A lid; the upper portion of a capsule, which on detachment permits the spores to escape.

A lid or covering to a chamber-like structure.

a hinged cap on a sporangium. Note: The operculum can also completely detach from the sporangium and float away, so not all opercula remain hinged. This is the main reason why you have to watch zoospore discharge so you can see if an operculum is present or not.

(oh - perk - yoo - lum) In Horseshoe crabs, it is the first of six pairs of gill books. Serves as a cover for the other five pairs. Houses the opening of the genital pores through which eggs and sperm are released from the body.

operculum = lid, cover. Used of the dermal bone covering the gill slit in actinopterygian fish, the plate-like bone found on the fenestra ovalis of amphibians (See The Ear.), etc.

flap-like fold of body wall, reinforced by cuticle (and/or calcification, that closes the orifice in cheilostomes.

A calcareous plate employed by many Molluscæ to close the aperture of their shell. The opercular valves of cirripedes are those which close the aperture of the shell. 137

Lid of cap like structure at one of both ends of certain worm eggs, ie, Trichuris, and fluke; the larval parasite emerges from the egg at the operculum.

See Gill Cover.

A lid or flap of skin covering an opening. Examples are the flap of skin covering the gills of some fish and the hard calcite cover of the snail shell opening when the snail is drawn up inside the shell.

The gill cover. A flexible bony plate that protects the sensitive gills.

This is the hard gill cover or the gill plates.

A lid or plate that covers the shell opening of some snails

The operculum is part of many shelled animals - it is the calcified, disc-shaped "trap door" that opens and closes to protect the animal inside its shell. The operculum from a species of sea snail called the Turban Shell (Turbo petholatus, found in the South Seas north of Australia) is eye-like with a natural cabochon shape and is used in jewelry. This jewelry was popular in Victorian Era Britain. Operculum is also called Pacific Cat's-eye.

Body covering for gills

A flap or lid-like covering over the opening of an ascus or sporangium. (Pl. opercula.) ( 15)

bony covering of the gills; protects the delicate gills underneath.

cap covering the tip of an ascus, which opens to release the spores.

The operculum is partly in the most posterior portion of the inferior frontal gyrus of the frontal lobe in the brain. One famous part of the operculum is Broca's area which plays an important role in conversation or speech production, reading and writing.

The operculum (plural : opercula or operculums) of gastropods is a corneous plate at the opening of the shell, attached dorsally to the foot. This fingernail-like structure seals the aperture, serving as a cover against predators when the snail body is retracted. It also enables the snail to survive periods of drought.

The operculum of a bony fish is the hard bony flap covering and protecting the gills. In most fish, the rear edge of the operculum roughly marks the division between the head and the body. The operculum is composed of four bones; the opercle, preopercle, interopercle, and subopercle.