Part 654

Spiny lobster. (Zoöl.) Same as Rock lobster, under Rock. See also Lobster.

Spin"y, n. See Spinny.

||Spi*o"de*a (?), n. pl. [NL., fr. Spio the typical genus.] (Zoöl.) An ||extensive division of marine Annelida, including those that are ||without oral tentacles or cirri, and have the gills, when present, ||mostly arranged along the sides of the body. They generally live in ||burrows or tubes.

Spi"ra*ble (?), a. [L. spirabilis.] Capable of being breathed; respirable. [Obs.] Nash.

Spir"a*cle (?), n.[L. spiraculum, fr. spirare to breathe: cf. F. spiracule. See Spirit.] 1. (Anat.) The nostril, or one of the nostrils, of whales, porpoises, and allied animals.

2. (Zoöl.) (a) One of the external openings communicating with the air tubes or tracheæ of insects, myriapods, and arachnids. They are variable in number, and are usually situated on the sides of the thorax and abdomen, a pair to a segment. These openings are usually elliptical, and capable of being closed. See Illust. under Coleoptera. (a) A tubular orifice communicating with the gill cavity of certain ganoid and all elasmobranch fishes. It is the modified first gill cleft.

3. Any small aperture or vent for air or other fluid.

Spi*rac"u*lar (?), a. Of or pertaining to a spiracle.

Spi*ræ"a (?), n. [L., fr. Gr. &?;&?;&?;, fr. &?;&?;&?; a coil.] (Bot.) A genus of shrubs or perennial herbs including the meadowsweet and the hardhack.

Spi*ræ"ic (?), a. (Chem.) Of, pertaining to, or derived from, the meadowsweet (Spiræa); formerly, designating an acid which is now called salicylic acid.

Spi"ral (?), a. [Cf. F. spiral. See Spire a winding line.] 1. Winding or circling round a center or pole and gradually receding from it; as, the spiral curve of a watch spring.

2. Winding round a cylinder or imaginary axis, and at the same time rising or advancing forward; winding like the thread of a screw; helical.

3. (Geom.) Of or pertaining to a spiral; like a spiral.

Spiral gear, or Spiral wheel (Mach.), a gear resembling in general a spur gear, but having its teeth cut at an angle with its axis, or so that they form small portions of screws or spirals. -- Spiral gearing, a kind of gearing sometimes used in light machinery, in which spiral gears, instead of bevel gears, are used to transmit motion between shafts that are not parallel. -- Spiral operculum, an operculum whih has spiral lines of growth. -- Spiral shell, any shell in which the whorls form a spiral or helix. -- Spiral spring. See the Note under Spring, n., 4.

Spi"ral (?), n. [Cf. F. spirale. See Spiral, a.] 1. (Geom.) A plane curve, not reëntrant, described by a point, called the generatrix, moving along a straight line according to a mathematical law, while the line is revolving about a fixed point called the pole. Cf. Helix.

2. Anything which has a spiral form, as a spiral shell.

Equiangular spiral,a plane curve which cuts all its generatrices at the same angle. Same as Logarithmic spiral, under Logarithmic. -- Spiral of Archimedes, a spiral the law of which is that the generatrix moves uniformly along the revolving line, which also moves uniformly.

Spi*ral"i*ty (?), n. The quality or states of being spiral.

Spi"ral*ly (?), adv. In a spiral form, manner, or direction.

Spi*ra`lo*zo"oid (?), n. [Spiral + zooid. So called because they often have a spiral form when contracted.] (Zoöl.) One of the special defensive zooids of certain hydroids. They have the form of long, slender tentacles, and bear lasso cells.

Spi"rant (?), n. [L. spirans, -antis, p. pr. of spirare to breathe. See Spirit.] (Phon.) A term used differently by different authorities; -- by some as equivalent to fricative, - - that is, as including all the continuous consonants, except the nasals m, n, ng; with the further exception, by others, of the liquids r, l, and the semivowels w, y; by others limited to f, v, th surd and sonant, and the sound of German ch, -- thus excluding the sibilants, as well as the nasals, liquids, and semivowels. See Guide to Pronunciation, §§ 197-208.

Spi*ran"thy (?), n. [Gr. &?;&?;&?; a coil + &?;&?;&?; flower.] (Bot.) The occasional twisted growth of the parts of a flower.

Spi*ra"tion (?), n. [L. spiratio, fr. spirare to breathe.] The act of breathing. [Obs.] Barrow.

Spire (?), v. i. [L. spirare to breathe. See Spirit.] To breathe. [Obs.] Shenstone.

Spire, n. [OE. spire, spir, a blade of grass, a young shoot, AS. spr; akin to G. spier a blade of grass, Dan. spire a sprout, sprig, Sw. spira a spar, Icel. spra.] 1. A slender stalk or blade in vegetation; as, a spire grass or of wheat.

An oak cometh up a little spire.

Chaucer.

2. A tapering body that shoots up or out to a point in a conical or pyramidal form. Specifically (Arch.), the roof of a tower when of a pyramidal form and high in proportion to its width; also, the pyramidal or aspiring termination of a tower which can not be said to have a roof, such as that of Strasburg cathedral; the tapering part of a steeple, or the steeple itself. "With glistering spires and pinnacles adorned." Milton.