Asterias belongs to the Phylum Echinodermata. The characteristic feature of echinoderm is the presence of endoskeleton made up of calcareous ossicles. They have a complete digestive system with ventrally placed mouth and dorsally placed anus. The organization seen is organ-system level. Echinoderms are triploblastic and coelomate animals. The adults are radially symmetrical where as the larvae are bilaterally symmetrical. Presence of water vascular system is the distinct feature of echinoderms. Examples are Sea Urchin, Brittle star, etc. Balanoglossus is a hemichordate whose adult as well as larva are bilaterally symmetrical. Obelia is a cnidarian whose adult as well as larva are radially symmetrical. Ascarisis a round whose adult as well as larva are bilaterally symmetrical.