from The American Heritage® Dictionary of the English Language, 4th Edition

  • n. Any of various invertebrate animals of the phylum Cnidaria, characterized by a radially symmetrical body with a saclike internal cavity, and including the jellyfishes, hydras, sea anemones, and corals. Also called coelenterate.
  • adj. Of, relating to, or belonging to the phylum Cnidaria.

from Wiktionary, Creative Commons Attribution/Share-Alike License

  • n. any of various invertebrate animals, such as jellyfish, hydras, sea anemones, corals and formerly sponges and ctenophores that belong to the phylum Cnidaria.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

  • n. radially symmetrical animals having saclike bodies with only one opening and tentacles with stinging structures; they occur in polyp and medusa forms


New Latin Cnīdāria, phylum name, from Greek knīdē, sea nettle.
(American Heritage® Dictionary of the English Language, Fourth Edition)
From New Latin cnidaria +‎ -an (Wiktionary)


  • A first striking finding was the high number of SOX gene sequences recovered from both the cnidarian and the ctenophore representatives (10 and 13 from C. hemisphaerica and P. pileus, respectively).

    As Expected

  • The ancestral cnidarian proto-Hox cluster is thought to have contained four Hox genes.

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  • Based on the clear clustering of the Wnt gene families it is highly unlikely that a single Wnt gene independently expanded in the cnidarian and vertebrate lineages.

    Death of a popular anti-ID argument

  • "Because all three main clades of bilaterian animals express a let-7 RNA that is temporally regulated, but cnidarian, poriferan and all non-animal species that we analysed do not express a detectable let-7 RNA, we propose that the gene evolved after the divergence of diploblastic and bilaterian animals"

    Teach the Controversy

  • Cnidarians are radially symmetrical, meaning that they're symmetrical around several axes, like the spokes in a bicycle wheel, whereas all the organisms depicted to the right of the cnidarian are bilaterally symmetrical, meaning they're only symmetrical around the head-to-tail axis (except for the echinoderms, which evolved radial symmetry independently).

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  • I'm going to briefly summarize an interesting new article on cnidarian Hox genes…unfortunately, it requires a bit of background to put it in context, so bear with me for a moment.

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  • Namapoikia rietoogensis gen. et sp. nov. is up to 1 meter in diameter and bears a complex and robust biomineralized skeleton; it probably represents a cnidarian or poriferan.

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  • A kind of colonial cnidarian - an animal with stinging cells related to anemones, corals and jellyfish.

    NYT > Home Page

  • Primary responsibilities are the expansion, organization, and maintenance of cloning libraries derived from cnidarian, ctenophore, crustacean, fish and avian model organisms.

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  • Project A kind of colonial cnidarian - an animal with stinging cells related to anemones, corals and jellyfish.

    NYT > Home Page


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