What is "coelenterata"

Coelentera \C[oe]*len"te*ra\or ||Coelenterata \C[oe]*len`te*ra"ta\, n. pl. [NL., fr. Gr. koi^los hollow + ? intestines.] (Zo["o]l.) A comprehensive group of Invertebrata, mostly marine, comprising the Anthozoa, Hydrozoa, and Ctenophora. The name implies that the stomach and body cavities are one. The group is sometimes enlarged so as to include the sponges.

Coelenterata is term encompassing two animal phyla, the Ctenophora (comb jellies) and the Cnidaria ( coral animals, true jellies, sea anemones, sea pens, and their allies). The name comes from the Greek "koilos" ("hollow bellied"), referring to the hollow body cavity common to these two phyla. They have very simple tissue organization, with only two layers of cells, external and internal and radial symmetry. Some of the examples are corals, sea anemone which are colonial and hydra, jelly fish which are solitary.Coelenterata have a closed circulatory system.