A star-shaped sea animal which creeps over rocks and sand, feeding on mussels and shellfish. The five rays are made of limestone plates, joined by a tough membrane. Under each ray is a groove with hundreds of tiny transparent tubes moving separately. The tubes act as feet and carry the animal forward. When the starfish feeds, it not only bends its rays into a cup shape to hold its prey, but numerous tiny suckers spring up to help. Star-fishes have a liver and intestines, and these organs extend into the five rays. They have nerves which end in a red eye-speck at the end of each ray. They do great damage to oyster beds, as they eat the oysters, which they force to open their shells. They are dredged from the beds and used as manure.