Echinodermata
Echinodermata is a phylum of strictly marine organisms, occurring throughout the world’s oceans. Echinodermata includes sea stars, brittle stars, sea urchins, sand dollars, sea cucumbers, and sea lilies. Echinoderms are tricoelomate deuterostomes, with a simple hemal/excretory system, decentralized nervous system, separate sexes (in most species,) and little to no skeletal systems.