Far from the northern latitudes of Maine, the diverse and productive ecosystem of the coral reef centers around coral, a group of organisms with a body design similar to that of an anemone. A single coral is called a polyp (POL-ip). Its tiny, saclike body comprises a stomach and a central opening lined with waving tentacles. Stony coral polyps use minerals from the sea to build supporting cups of calcium carbonate around their bodies, while "soft" coral polyps make flexible supports of protein. Polyps generally live together in a colony, their individual cups fusing together to form a large coral skeleton. As they grow and die, new polyps form along the outer surface of the coral and continually expand the structure outward. Some coral, like brain coral, may have many convolutions that appear like a human brain. This type of coral may live for up to a century on a reef that is ten times its age.