Locomotion In Star fish

 Locomotion In Star fish: 

    In Star fish locomotion in controlled by a special water vascular system. Water is drawn into the body through a small opening in the central disc and is passed through a ring canal to five radial canals one running along each arm. Along each of these cannals a large number of hollow, muscular tube feet are present. The upper part of a tube foot, connected with the canal, is a bulb shaped ampulla whereas its bottom part is a sucker. When ampullae contract water forces the tube feet to lengthen and suckers become attached to on object. When sucker muscles contract the water is pushed back into the ampullae, making the tube feet flaccid, losing the grip and the star fish is pulled forward. Using its hundreds of feet a star fish creeps along the rock and other solid objects in the sea. Using its arms, it can also swim in water.