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Any one of the large bivalve mollusks found on the open seacoast, especially those of the family Mactridæ, as the common American species. (Mactra, or Spisula, solidissima); -- called also beach clam, and surf clam.

In a steamship, a cock or valve close to the vessel's side, for closing a pipe which communicates with the sea.

Any large marine univalve shell of the genus Triton. See Triton.

A part or surface on which another part or surface rests; as, a valve seat. Seat worm (Zoöl.), the pinworm.

r bone (Anat.), a bone of the carpus; the lunar. See Lunar, n. -- Semilunar, or Sigmoid, valves (Anat.), the valves at the beginning of the aorta and of the pulmonary artery which prevent the blood from flowing back into the ventricle.

Bearing a partition; -- said of the valves of a capsule.

Breaking from the partitions; -- said of a method of dehiscence in which the valves of a pod break away from the partitions, and these remain attached to the common axis.

engine into any desired position indicated by that of the hand lever, which controls the valve of the motor.

Any long, slender, worm-shaped bivalve mollusk of Teredo and allied genera. The shipworms burrow in wood, and are destructive to wooden ships, piles of wharves, etc. See Teredo.

ent the passage of, as steam through a pipe, or water through a flume, by closing a cock, valve, or gate. -- To shut out, to preclude from entering; to deny admission to; to exclude; as, to shut out rain by a tight roof. -- To shut together, to unite; to close, especially to close by welding. -- To shut up. (a) To c…

of the colon before it terminates in the rectum. See Illust. under Digestive. -- Sigmoid valves. (Anat.) See Semilunar valves, under Semilunar.

An oblong or elongated seed vessel, consisting of two valves with a dissepiment between, and opening by sutures at either margin. The seeds are attached to both edges of the dissepiment, alternately upon each side of it.

o. Called also kisutch, whitefish, and white salmon. -- Silver shell (Zoöl.), a marine bivalve of the genus Anomia. See Anomia. -- Silver steel, an alloy of steel with a very small proportion of silver. -- Silver stick, a title given to the title field officer of the Life Guards when on duty at the palace. [Eng.] Th…

One of the tubes or folds of the mantle border of a bivalve or gastropod mollusk by which water is conducted into the gill cavity. See Illust. under Mya, and Lamellibranchiata.

A tribe of bivalve mollusks in which the posterior mantle border is prolonged into two tubes or siphons. Called also Siphoniata. See Siphon, 2 (a), and Quahaug.

Any one of several large bivalve shells, sometimes used for skimming milk, as the sea clams, and large scallops.

A slide valve. Slide box (Steam Engine), a steam chest. See under Steam. -- Slide lathe, an engine lathe. See under Lathe. -- Slide rail, a transfer table. See under Transfer. -- Slide rest (Turning lathes), a contrivance for holding, moving, and guiding, the cutting tool, made to slide on ways or guides by screws o…

An artifical passage for water, fitted with a valve or gate, as in a mill stream, for stopping or regulating the flow; also, a water gate of flood gate.

snail, Pond snail, etc. See under Ear, Edible, etc. -- Snail borer (Zoöl.), a boring univalve mollusk; a drill. -- Snail clover (Bot.), a cloverlike plant (Medicago scuttellata, also, M. Helix); -- so named from its pods, which resemble the shells of snails; -- called also snail trefoil, snail medic, and beehive. -…

from Snift. Snifting valve, a small valve opening into the atmosphere from the cylinder or condenser of a steam engine, to allow the escape of air when the piston makes a stroke; -- so called from the noise made by its action.