An order of the cnidarian subclass Zoantharia (Hexacorallia) known as the sea anemones, the most widely distributed of the anthozoans. They have even been discovered in frigid waters. Usually they are solitary animals which live under the low-tide mark attached to some solid object by a basal expansion or pedal disk. They feed on prey such as copepods, mollusks, annelids, crustaceans, and fishes. The burrowing species, like Edwardsia, Halcampella, and Harenactis, lack a pedal disk and bury their elongated bodies in the soft sediment of oceans. The actinians move rather actively. Gonactinia and Boloceroides can swim by using their tentacles.