Echinoderms
type: Class
subclass of: RCBYQBHCTDnnpanK0HJ0I7w
definition: Echinoderms are a phylum of marine invertebrates known as Echinodermata, characterized by their radial symmetry, a water vascular system, and a calcareous endoskeleton. This group includes starfish, sea urchins, sand dollars, and sea cucumbers, and they play vital roles in marine ecosystems.