Defn: Any species or marine hydroids, of the genus Hydractinia and allied genera. These hydroids form, by their rootstalks, a firm, chitinous coating on shells and stones, and esp. on spiral shells occupied by hermit crabs. See Illust. of Athecata.
HYDRAEMIA
Hy*dræ"mi*a, n. Etym: [NL., fr. Gr. "y`dwr water + (Med.)
Defn: An abnormally watery state of the blood; anæmia.
HYDRAGOGUE Hy"dra*gogue, a. Etym: [L. hydragogus conveying off water, Gr. "y`dwr water + hydragogue.] (Med.)
Defn: Causing a discharge of water; expelling serum effused into any part of the body, as in dropsy. — n.
Defn: A hydragogue medicine, usually a cathartic or diuretic.
HYDRAMIDE
Hy*dram"ide, n. Etym: [Hydr- + -amide.] (Chem.)
Defn: One of a group of crystalline bodies produced by the action of ammonia on certain aldehydes.
HYDRAMINE
Hy*dram"ine, n. Etym: [Hydroxyl + amine.] (Chem.)
Defn: One of a series of artificial, organic bases, usually produced as thick viscous liquids by the action of ammonia on ethylene oxide. They have the properties both of alcohol and amines.