Asteroids and echinoids, which use spines and tube feet in locomotion, may move forward with any area of the body and reverse direction without turning around. The feet may be used either as levers, by means of which the echinoderm steps along a surface, or as attachment mechanisms that pull the animal. Sea daisies presumably move in the same way. Ophiuroids tend to move by thrashing the arms in one of several possible methods, including a rowing motion in which strokes are taken by two pairs of extended arms; the fifth arm either is extended forward in the direction in ...(100 of 8705 words)