Gill arches

Gill Gill (g[i^]l), n. [Dan. gi[ae]lle, gelle; akin to Sw. g["a]l, Icel. gj["o]lnar gills; cf. AS. geagl, geahl, jaw.] 1. (Anat.) An organ for aquatic respiration; a branchia. [1913 Webster]

Fishes perform respiration under water by the gills. --Ray. [1913 Webster]

Note: Gills are usually lamellar or filamentous appendages, through which the blood circulates, and in which it is exposed to the action of the air contained in the water. In vertebrates they are appendages of the visceral arches on either side of the neck. In invertebrates they occupy various situations. [1913 Webster]

2. pl. (Bot.) The radiating, gill-shaped plates forming the under surface of a mushroom. [1913 Webster]

3. (Zo["o]l.) The fleshy flap that hangs below the beak of a fowl; a wattle. [1913 Webster]

4. The flesh under or about the chin. --Swift. [1913 Webster]

5. (Spinning) One of the combs of closely ranged steel pins which divide the ribbons of flax fiber or wool into fewer parallel filaments. [Prob. so called from F. aiguilles, needles. --Ure.] [1913 Webster]

{Gill arches}, {Gill bars}. (Anat.) Same as {Branchial arches}.

{Gill clefts}. (Anat.) Same as {Branchial clefts}. See under {Branchial}.

{Gill cover}, {Gill lid}. See {Operculum}.

{Gill frame}, or {Gill head} (Flax Manuf.), a spreader; a machine for subjecting flax to the action of gills. --Knight.

{Gill net}, a flat net so suspended in the water that its meshes allow the heads of fish to pass, but catch in the gills when they seek to extricate themselves.

{Gill opening}, or {Gill slit} (Anat.), an opening behind and below the head of most fishes, and some amphibians, by which the water from the gills is discharged. In most fishes there is a single opening on each side, but in the sharks and rays there are five, or more, on each side.

{Gill rakes}, or {Gill rakers} (Anat.), horny filaments, or progresses, on the inside of the branchial arches of fishes, which help to prevent solid substances from being carried into gill cavities. [1913 Webster]