http://tolweb.org/Echinodermata | A marine invertebrate of the phylum Echinodermata, such as a starfish, sea urchin, or sea cucumber. Echinoderms are characterized by their radial symmetry, water vascular system and internal skeleton. The most striking feature of all echinoderms is their pentamerous radial symmetry. That is, the body can be divided into five parts (or appendages) which point outward from the center of the body. |