Sea anemones belong to the class Anthozoa from the phylum Coelenterata (Cnidaria). The Anthozoa are marine polyps of flower like form, of small to large size and rather firm texture, with a tendency toward biradial symmetry in arrangement of the gullet and internal septa. Besides the familiar sea anemones and stony corals, this class includes the soft, horny, and stony, and black corals, the colonial sea pens and sea pansies, and others, all of which lack a medusa stage. They abound in warm shallow waters, but some inhabit polar seas.