A cytochemical study of the basic protein composition in the sperm of seven species of anurans has revealed that their sperm histones fall into only two classes of the five proposed by Bloch (1969); (1) the Rana type, which is similar to the histones found in the somatic cells; and (2) the Mytilus type, which appears to contain more arginine than that in Rana but less arginine than the arginine-rich histones of mouse and grasshopper sperm. Basic proteins free of DNA were not observed in the sperm.