sentences:  During locomotion, the tube feet are assisted by the spines which can be used for pushing the body along or to lift the test off the substrate.Movement is generally related to feeding, with the red sea urchin ("Mesocentrotus franciscanus") managing about a day when there is ample food, and up to a day where there is not.An inverted sea urchin can right itself by progressively attaching and detaching its tube feet and manipulating its spines to roll its body upright.