Water vascular system is found in echinoderms. Echinoderms are marine invertebrates that include the sea urchins, starfish, brittle stars, and sea cucumbers. Water vascular system is a division of the coelom and most distinctive feature of echinoderms. It is a system of canals and appendages of body wall. It is also termed as ambulacral system. It functions as a means of locomotion. It consists of madreporite or sieve plate, stone canal, water ring or ring canal, radial canals and podia or tube feet.