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Any one of very numerous species of small spiral gastropods of the genus Rissoa, or family Rissoidæ, found both in fresh and salt water.

pe (Antilope bezoartica, or cervicapra), noted for its beauty and swiftness. It has long, spiral, divergent horns.

species of marine gastropods of the genus Scalaria, or family Scalaridæ, having elongated spiral turreted shells, with rounded whorls, usually crossed by ribs or varices. The color is generally white or pale. Called also ladder shell, and wentletrap. See Ptenoglossa, and Wentletrap.

r a cylindrical perforation, having a continuous rib, called the thread, winding round it spirally at a constant inclination, so as to leave a continuous spiral groove, between one turn and the next, -- used chiefly for producing, when revolved, motion or pressure in the direction of its axis, by the sliding of the thr…

An ornament formed of undulations giving off spirals or sprays, usually suggestive of plant form. Roman architectural ornament is largely of some scroll pattern.

opod Mollusca having a heart with two auricles and one ventricle. The shell may be either spiral or shieldlike.

They secrete a calcareous tube, which is usually irregularly contorted, but is sometimes spirally coiled. The worm has a wreath of plumelike and often bright-colored gills around its head, and usually an operculum to close the aperture of its tube when it retracts.

ing the whorls of the spire revolving or rising to the left; reversed; -- said of certain spiral shells.

Rising spirally from right to left (of the spectator); sinistrorse.

Any species of Pleurotomaria, a genus of beautiful, pearly, spiral gastropod shells having a deep slit in the outer lip. Many fossil species are known, and a few living ones are found in deep water in tropical seas.

A spiral cam, or a flat piece of metal of spirally curved outline, used for giving motion to, or changing the position of, another part, as the hammer tail of a striking clock.

To wind round spirally, as a large rope with a smaller, or with cord, the small rope lying in the spaces between the strands of the large one; to worm.

Any one of several species of handsome marine spiral shells of the genus Solarium and allied genera. The shell is conical, and usually has a large, deep umbilicus exposing the upper whorls. Called also perspective shell.

An electrodynamic spiral having the conjuctive wire turned back along its axis, so as to neutralize that component of the effect of the current which is due to the length of the spiral, and reduce the whole effect to that of a series of equal and parallel circular currents. When traversed by a current the solenoid exhi…

Drawn out from a heated solid bar, as by a process of spiral rolling which first hollows the bar and then expands the cavity by forcing the bar over a pointed mandrel fixed in front of the rolls; - - said of a weldless tube.

Having spines arranged spirally. See Spicule.

A spiral; a curl; a whorl; a twist. Dryden.

thyris, and allied genera, in which the long calcareous supports of the arms form a large spiral, or helix, on each side.

A genus of common motile microörganisms (Spirobacteria) having the form of spiral-shaped filaments. One species is said to be the cause of relapsing fever.

of cephalopods having a multilocular, internal, siphunculated shell in the form of a flat spiral, the coils of which are not in contact.