What Is A Crown Of Thorns Starfish?

The starfish is built around a central point like a wheel, many of them having five arms. But the crown-of-thorns variety usually has sixteen arms! And as its name indicates, its two-foot-wide topside is covered with long, poisonous thorns.
From a central mouth on the starfish's underside radiate sixteen grooves, one in each arm. Lining these grooves are rows of slender tubes. They are called "tube feet." At the end of each tube foot is a suction cup, and there are hundreds of these on each arm.
Most helpful to the starfish when he is hungry, these feet enable him to grip tightly, with a force equal to about twenty-five pounds to the square inch. They can pull open even large oysters, to feed upon them. When the starfish dines on coral, it simply folds its many arms over its potential meal, and gets a good foothold. Then an amazing thing happens: The starfish turns its billowy stomach inside out through its mouth, spreads it over its victim like a collapsed parachute and pours digestive juices on the coral—and the meal is enjoyed.
As with other starfish, the crown of thorns is a remarkable creature. For one thing, it can grow new arms if old ones are broken off. In fact, an entire animal can grow from only one arm that has a portion of its central disk.