(Science: zoology) An extensive order of hydrozoa or acalephae.

alternative forms: Hydroida.

this order includes the hydras and the free-swimming hydromedusae, 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.

Origin: NL. See hydra, and -oid.

Retrieved from "http://www.biology-online.org/bodict/index.php?title=Hydroidea&oldid=36514"
First | Previous (Hydroid) | Next (Hydroideas) | Last
Please contribute to this project, if you have more information about this term feel free to edit this page.