Ключевые слова: 1, animal, background, bivalve, bright, calcareous, calcium, case, chitin, clam, close, coating, concave, cream, creamy, decorative, empty, exeskeleton, gastropod, hard, hollow, isolated, ivory, layer, light, marine, mollusc, molluscan, mollusk, molusc, mussel, nacreous, nacrous, neritiform, object, ocean, one, outer, pearl, protective, scallop, sea, seashell, shell, shelter, single, snail, spiral, white, whole,