An electrophoretic analysis of the fate of sperm and egg histones of the sea urchin S̲t̲r̲o̲n̲g̲y̲l̲o̲c̲e̲n̲t̲r̲o̲t̲u̲s̲ p̲u̲r̲p̲u̲r̲a̲t̲u̲s̲ after fertilization : with an analysis of the possible role that proteolytic enzymes play in the fate of the g...