The simplest eumetazons are the Radiata, a loose group that includes jellyfish, corals, and comb jellies. Most of them belong in the phylum Cnidaria, except for the comb jellies, which comprise the phylum Ctenophora. Radiatans have what is called radial symmetry, where they can be divided into two even halves in many planes, like a wheel or a circle. All cnidarians have special cells called cnidocytes, which produce the sting. Comb jellies have no such cells and are harmless to humans. | The simplest eumetazons are the Radiata, a loose group that includes jellyfish, corals, and comb jellies. Most of them belong in the phylum Cnidaria, except for the comb jellies, which comprise the phylum Ctenophora. Radiatans have what is called radial symmetry, where they can be divided into two even halves in many planes, like a wheel or a circle. All cnidarians have special cells called cnidocytes, which produce the sting. Comb jellies have no such cells and are harmless to humans. |