operculum


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operculum

1. Zoology
a. the hard bony flap covering the gill slits in fishes
b. the bony plate in certain gastropods covering the opening of the shell when the body is withdrawn
2. Botany the covering of the spore-bearing capsule of a moss
3. Biology any other covering or lid in various organisms

Operculum

 

the fold of skin that covers the outside of the gill slits in the majority offish (except the shark and ray) and in the larvae of amphibians, especially tadpoles. The operculum of fish of the class Osteichthyes has bones. In the majority offish the operculum plays an active role in breathing: when it is lifted, a vacuum is created in the gill cavity, and water passes from the mouth and pharyngeal cavities into the gill cavity by way of the gill apparatus. It is possible to determine the age of some fish according to the annual rings on the operculum bones.

operculum

[ō′pər·kyə·ləm]
(anatomy)
The soft tissue partially covering the crown of an erupting tooth.
That part of the cerebrum which borders the lateral fissure.
(biology)
A lid, flap, or valve.
A lidlike body process.
References in periodicals archive ?
However, we have created two new categories for radiolar eyes located on the operculum of serpulids: type oS (opercular-simple) and type oC (opercular-compound) (Fig.
Precentral Artery (PCA): The artery extends out on the medial surface of the operculum and supplies the posterior parts of the middle and inferior frontal gyri as well as the lower parts of the precentral gyrus.
The operculum is a hard and horny structure that exists in many marine and freshwater snails.
A common way to identify them is by their light olive color and the distinct bright red outer rim on their ear flap or operculum.
4 SELECTED EXAMPLES OF SINGULAR AND PLURAL FORMS Singular/Plural Example a/ae gingiva, gingivae ex/ices index, indices i/us alveoli, alveolus is/es diagnosis, diagnoses on/a ganglion, ganglia um/a operculum, opercula BOX 1.
8): head brownish dorsally, grading to whitish ventrally; operculum with blackish stripe crossing uppermost portion with silvery patch immediately below; light brown on back, grading to whitish ventrally; each scale of side with thin brown margins imparting overall network appearance; blackish mid-lateral stripe on side from pectoral-fin base to caudal-fin base, poorly developed and interrupted on anterior half, but distinctly wider (covering up to 3 scales) on posterior half; second dorsal, anal, pelvic and caudal fins generally dusky grey with blackish sub-marginal stripe (more prominent on dorsal fin) and narrow whitish margin on dorsal and anal; caudal fin with narrow, blackish upper and lower margins; pectoral fins translucent.
Similarly pericoronitis manifested most commonly in class II impacted molars which is prob- ably because they are half visible in the mouth with an operculum and do not have a good inter-cuspation with maxillary counterparts.
Opercular pad elliptical, ~80% as wide as dorsal surface of foot; attachment with operculum occupying ~ 70% of its area (Fig.