Sea anemones are a group of water-dwelling, predatory animals of the order Actiniaria; they are named after the anemone, a terrestrial flower. Sea anemones are classified in the phylum Cnidaria, class Anthozoa, subclass Zoantharia. Anthozoa often have large polyps that allow for digestion of larger prey and also lack a medusa stage. As cnidarians, sea anemones are closely related to corals, jellyfish, tube-dwelling anemones, and Hydra.