What is Siphonophore?
[[File:Marrus orthocanna.jpg|thumb|right|250px|'''''Marrus orthocanna''''' is a [[species]] of [[pelagic]] siphonophore, a colonial animal. It has [[zooid]]s, some of which are [[polyp]]s and some [[Medusa (biology)|medusae]].<br/> It lives in the [[Arctic]] and other cold, deep waters, swimming independently in mid-ocean.<ref name=Siph>[http://www.siphonophores.org/ Siphonophores] Retrieved 2011-10-01.</ref>]] The '''Siphonophores''' are an [[Order (biology)|order]] of [[cnidaria]]n [[invertebrate]]s in the class [[Hydrozoa]]. The [[Portuguese man o' war]] is an example. A siphonophore is not a single animal. It is a [[Colony (biology)|colony]] of four kinds of [[zooid]]s. Zooids are very small, highly modified individuals. All the zooids in a colony are genetically identical. These zooids are specialized [[polyp]]s and [[Medusa (biology)|medusoids]].<ref>Grzimek B. Schlager N. & Olendorf D. 2003. ''Grzimek's Animal life encyclopaedia''. Thomson Gale.</ref> Though structurally similar to other cnidarians, the zooids do not live by themselves: they are attached to each other. Each type of zooid is not self-sufficient. It depends for survival on the others doing what it cannot do by itself. So close do the zooids fit together that the colony looks like a single individual. It was a triumph of 19th century biology to discover the real nature of the siphonophores. *''[[Bathyphysa conifera]]'' *[[Portuguese man o' war]] == References == {{Reflist}} [[Category:Cnidarians]]