Note: The body is a simple tube, having a mouth at one extremity, surrounded by a circle of tentacles with which it captures its prey. Young hydras bud out from the sides of the older ones, but soon become detached and are then like their parent. Hydras are remarkable for their power of repairing injuries; for if the body be divided in pieces, each piece will grow into a complete hydra, to which fact the name alludes. The zooids or hydranths of marine hydroids are sometimes called hydras.
4. (Astron.)
Defn: A southern constellation of great length lying southerly from
Cancer, Leo, and Virgo.
HYDRACHNID
Hy*drach"nid, n. Etym: [Hydr- + arachnid.] (Zoöl.)
Defn: An aquatic mite of the genus Hydrachna. The hydrachids, while young, are parasitic on fresh-water mussels.
HYDRACID
Hy*drac"id, n. Etym: [Hydr- + acid: cf. F. hydracide.] (Chem.)
Defn: An acid containing hydrogen; — sometimes applied to distinguish acids like hydrochloric, hydrofluoric, and the like, which contain no oxygen, from the oxygen acids or oxacids. See Acid.
HYDRACRYLIC
Hy`dra*cryl"ic, a. Etym: [Hydr- + acrylic.] (Chem.)
Defn: Pertaining to, or designating, an isomeric variety of lastic acid that breaks down into acrylic acid and water.
HYDRACTINIAN
Hy`drac*tin"i*an, n. Etym: [See Hydra, and Actinia.] (Zoöl.)