Echinoderms are marine animals of the class Echinoidea that are characterized by radial symmetry, such as the [[sea urchin]] or with multiple arms radiating from a central body, such as [[Starfish]]. | Echinoderms are marine animals of the class Echinoidea that are characterized by radial symmetry, such as the [[sea urchin]] or with multiple arms radiating from a central body, such as [[Starfish]]. |