Sessile aquatic animal forming mosslike colonies of small polyps each having a curved or circular ridge bearing tentacles,attach to stones or seaweed and reproduce by budding.

• 固着型水生动物，形成象苔藓一样珊瑚虫群体，每只有弯曲或圆形的背脊，附着在石头或海藻上，通过芽接繁殖。