Siph"i*lis (?), n. (Med.) Syphilis.
Si"phoid (?), n. [L. sipho a siphon + -oid: cf. F. vase siphoïde.] A
siphon bottle. See under Siphon, n.
Si"phon (?), n. [F. siphon, L. sipho, -onis, fr. Gr. &?;&?;&?; a
siphon, tube, pipe.] 1. A device, consisting of a pipe or tube bent so
as to form two branches or legs of unequal length, by which a liquid
can be transferred to a lower level, as from one vessel to another,
over an intermediate elevation, by the action of the pressure of the
atmosphere in forcing the liquid up the shorter branch of the pipe
immersed in it, while the continued excess of weight of the liquid in
the longer branch (when once filled) causes a continuous flow. The flow
takes place only when the discharging extremity of the pipe ia lower
than the higher liquid surface, and when no part of the pipe is higher
above the surface than the same liquid will rise by atmospheric
pressure; that is, about 33 feet for water, and 30 inches for mercury,
near the sea level.
2. (Zoöl.) (a) 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. (b) The anterior
prolongation of the margin of any gastropod shell for the protection of
the soft siphon. (c) The tubular organ through which water is ejected
from the gill cavity of a cephaloid. It serves as a locomotive organ,
by guiding and confining the jet of water. Called also siphuncle. See
Illust. under Loligo, and Dibranchiata. (d) The siphuncle of a
cephalopod shell. (e) The sucking proboscis of certain parasitic
insects and crustaceans. (f) A sproutlike prolongation in front of the
mouth of many gephyreans. (g) A tubular organ connected both with the
esophagus and the intestine of certain sea urchins and annelids.