National Geographic : 1934 Jun
MULTI-HUED MARVELS OF A CORAL REEF @ National Geographic Society TINY MAGICIANS ARE BORN TO TURN SEA WATER TO STONE Myriads of pear-shaped larvae of pinhead size (inset, highly magnified) are shown pouring from the mouths of a Radiant Star Coral, Siderastrearadians (upper left). They swim by waving their hairs, then anchor, become domelike, and grow stinging tentacles for catching and stuffing microscopic animals into hungry mouth-slits. Now each polyp-meaning "many-footed"-turns chemist. It gives off ammonia and carbon dioxide. The latter, combining with lime in the water, forms limestone for coral skeletons. ~; ~:"