| a basic body plan in which the organism can be divided into similar halves by passing a plane at any angle along a central axis, characteristic of sessile and bottom-dwelling animals, as the sea anemone and starfish. |
| radial symmetry n. Symmetrical arrangement of constituents, especially of radiating parts, about a central point. radially symmetrical adj. |
| radial symmetry
Symmetrical arrangement of parts of an organism around a single main axis, so that the organism can be divided into similar halves by any plane that contains the main axis. The body plans of echinoderms, ctenophores, cnidarians, and many sponges and sea anemones show radial symmetry. Compare bilateral symmetry. |
