Hydroidea
Pronunciation : Hy*droi"de*a
Part of Speech : n.
Etymology : [NL. See Hydra, and -oid.] (Zo?l.)
Definition : Defn: An extensive order of Hydrozoa or Acaleph?. [Written also Hydroida.]
Note: This order includes the hydras and the free-swimming hydromedus?, together with a great variety of marine attached hydroids, many of which grow up into large, elegantly branched forms, consisting of a vast number of zooids (hydranths, gonophores, etc.), united by hollow stems. All the zooids of a colony are produced from one primary zooid, by successive buddings. The Siphonophora have also been included in this order by some writers. See Gymnoblastea, Hydromedusa, Gonosome, Gonotheca.
pl.
Source : Webster's Unabridged Dictionary, 1913