Sea anemones are a group of water-dwelling, predatory animals of the order Actiniaria. They are named for the anemone, a terrestrial flower. Sea anemones are classified in the phylum Cnidaria, class Anthozoa, subclass Hexacorallia. [1] Anthozoa often have large polyps that allow for digestion of larger prey and also lack a medusa stage.[2] As cnidarians, sea anemones are related to corals, jellyfish, tube-dwelling anemones, and Hydra. Original public domain image from Flickr