George Cuvier classified animals with radial symmetry in the taxon Radiata (Zoophytes), which is now generally accepted to be an assemblage of different animal phyla that do not share a single common ancestor (a polyphyletic group). Most radially symmetric animals are symmetrical about an axis extending from the center of the oral surface, which contains the mouth, to the center of the opposite (aboral) end. Animals in the phyla Cnidaria and Echinodermata generally show radial symmetry, although many sea anemones and some corals within the Cnidaria have bilateral symmetry defined by a single structure, the siphonoglyph. Radial symmetry is especially suitable for sessile animals such as the sea anemone, floating animals such as jellyfish, and slow moving organisms such as starfish ; whereas bilateral symmetry favours locomotion by generating a streamlined body.