The sea urchin also has a set of tube feet whose muscles cause suction, and it moves using the water vascular system similar to that of the starfish. They also use their muscles to move their skeleton and spines on top of them. The connective tissues of the tubed feet allow the to stretch longitudinally to allow movement. Unique to the green sea urchin though is the painful venom that is at the base of the spines and the venomous pincers at the base of said spine that give the urchin its vibrant warning colors.
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