Any of various invertebrate animals of the phylum Coelenterata,characterized by a radially symmetrical body with a saclike internal cavity,and including the jellyfishes,hydras,sea anemones,and corals.

• 腔肠动物，一种腔肠动物门的无脊椎动物，特征是有囊状腔的辐射对称体，包括水母、水螅、海葵和珊瑚。