National Geographic : 1938 Sep
SEA FLOOR AQUARELLES FROM TONGAREVA ( National Geographic Society Painted by Else Bostelmann under direction Roy W. Miner TOUCH A GIANT CLAM'S LIPS AND ITS SHELLS SNAP SHUT LIKE STEEL-TRAP JAWS Pearl divers must take care not to get hand or foot caught in the viselike grip. Open shells pro trude from the corals or stand on edge on sandy bottoms. When distended, their thick mantles pour over the wavy shells in contrasting patterns of indigo and sapphire, purple and turquoise, green and black, orange and brown. Through mantle openings a food-bearing stream of sea water is pumped. A pair of huge clams (Tridacna gigantea), taken in Australia and now exhibited at the American Museum of Natural History, weighs 5792 pounds. Those in Tongareva ( T. compressa) are a foot long.