National Geographic : 1934 Jun
THE NATIONAL GEOGRAPHIC MAGAZINE © National Geographic Society VORACIOUS POLYPS EAT SO MUCH THEY BECOME "TWO OTHER FELLOWS" Overflowing with life and energy, each may start a colony by budding off other individuals like itself or splitting in half. Those pictured at the bottom divide so swiftly that they produce massive, compact coral mounds. Above these mounds others build submarine "skyscrapers," because they divide less frequently and pile up limestone more rapidly. Lining its stomach cavity each worker grows "vegetable gardens" of minute plants or algae, which may be digested outright to vary a carnivorous diet.