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A kind of spiral curve found in certain univalve shells. Agassiz.

Having elevations or depressions in form like one half of a bivalve shell; -- applied principally to a surface produced by fracture.

), of the oboe family. (b) A brass instrument, with cupped mouthpiece, and furnished with valves or pistons, now used in bands, and, in place of the trumpet, in orchestras. See Cornet-à-piston. (c) A certain organ stop or register.

A brass wind instrument, like the trumpet, furnished with valves moved by small pistons or sliding rods; a cornopean; a cornet.

The lap of a slide valve.

The valve gearing or mechanism by which steam is cut off from entering the cylinder of a steam engine after a definite point in a stroke, so as to allow the remainder of the stroke to be made by the expansive force of the steam already let in. See Expansion gear, under Expansion.

A genus of marine univalve shells; the gondola.

The free-swimming, bivalve larva of certain Bryozoa.

A genus of small, bivalve, freshwater Crustacea, belonging to the Ostracoda; also, a member of this genus.

That which damps or checks; as: (a) A valve or movable plate in the flue or other part of a stove, furnace, etc., used to check or regulate the draught of air. (b) A contrivance, as in a pianoforte, to deaden vibrations; or, as in other pieces of mechanism, to check some action at a particular time. Nor did Sabrina's p…

A pneumatic or hydraulic cushion for a falling weight, as in the valve gear of a steam engine, to prevent shock.

Decapitated; worn or cast off in the process of growth, as the apex of certain univalve shells.

iate mollusks having an anterior and posterior adductor muscle, as the common clam. See Bivalve.

A genus of Branchiopoda, having a disklike shell, attached by one valve, which is perforated by the peduncle.

Having the form of a disk, as those univalve shells which have the whorls in one plane, so as to form a disk, as the pearly nautilus. Discoid flower (Bot.), a compound flower, consisting of tubular florets only, as a tansy, lacking the rays which are seen in the daisy and sunflower.

A genus of large univalve mollusks, including the partridge shell and tun shells.

A genus of bivalve shells of which one species (D. polymorpha) is often so abundant as to be very troublesome in the fresh waters of Europe.

A marine gastropod, of several species, which kills oysters and other bivalves by drilling holes through the shell. The most destructive kind is Urosalpinx cinerea. Bow drill, Breast drill. See under Bow, Breast. -- Cotter drill, or Traverse drill, a machine tool for drilling slots. -- Diamond drill. See under Diamon…

A fruit consisting of pulpy, coriaceous, or fibrous exocarp, without valves, containing a nut or stone with a kernel. The exocarp is succulent in the plum, cherry, apricot, peach, etc.; dry and subcoriaceous in the almond; and fibrous in the cocoanut.

ine, a steam pump in which two steam cylinders are placed side by side, one operating the valves of the other. -- Duplex querela Etym: [L., double complaint] (Eccl. Law), a complaint in the nature of an appeal from the ordinary to his immediate superior, as from a bishop to an archbishop. Mozley & W. -- Duplex telegr…