Phylum-Echinodermata (Echino-spiny, derma-skin)

Explanation

(i) Calcareous spines are present on the body of these animals, hence, are called as Echinoderms.
(ii) These animals are found only in ocean.
(iii) Their body is triploblastic, eucoelornate. It is radially symmetrical in adult stage. However, shows bilateral symmetry in larval stage.
(iv) They perform locomotion with the help of tube feet. Tube feet are also useful to catch the prey. Some animals are sedentary.
(v) They have skeleton made up of calcareous spines and /or ossicles (plates).
(vi) These animals are unisexual.
(vii) These animals have good ability of regeneration .e.g. Starfish, Brittle star, Sea-urchin, Sea cucumber, etc.