Observations on destruction of spermatozoa in the cauda epididymidis and proximal vas deferens of non-seasonal male mammals.

The electron microscope has been used to examine luminal spermatozoa from the cauda epididymidis and proximal vas deferens of rats, mice, hamsters and guinea pigs. Free in the lumen of all species are accumulations of a dense material within which are vesicles, granules and dense bodies, as well as spermatozoa. The spermatozoa are undergoing a process of degeneration as judged by a loss of plasma membrane from both heads and tails and further disruption of acrosomal membranes, mitochondrial sheaths and outer dense fibers. Disruption of spermatozoa also occurs outside these obvious dense masses when the luminal protein precipitated by the fixation procedure has contact with the spermatozoon. Intact spermatozoa are separated from luminal material by a clear "halo".