National Geographic : 1961 Feb
KODACHROMES( NATIONALGEOGRAPHICSOCIETY Velvety mantles spill from cantaloupe-sized tri dacna clams, their shells agape in a shallow pool of the Great Barrier Reef. The mantles, no two colored alike, unfold to the sun to benefit algae living on mutual-benefit terms with the clams. Splash of water closes a crusty goliath, Tridacna gigas, one of the Great Barrier Reef's giants. This clam weighs 60 pounds; some attain 500 pounds. Tales abound of divers trapped by the toothed shells, but evidence is lacking.