Presence of Ambulacral system (water vascular system) is the characteristic features of phylum Echinodermata. A perforated plate called Madreporite is present in this system. The pores of the Madreporite allow water into the system. Tube feet in this system helps in locomotion and respiration additional function are adhesion and food capturing.
The proper circulatory system is absent. There is an open types haemal system through which flows haemolymph. The so called blood is without respiratory segment and heart is absent.
Simple digestive tract, alimentary canal is coiled.