The fine structure of the sperm and spermatogenesis of the Donax striatus are described. The morphology of the spermatozoa is classified as of a primitive type with a head, mid-piece with four mitochondria and tail. The head shows a complex acrosome, typical of heterodont bivalves. During spermatogenesis the nuclear chromatin shows granular condensation. The present paper describes detailed observations of the espermatozoa.
Ultrastructure; Spermatozoa; Mollusca Bivalvia