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