The mesonephric duct becomes the epididymis and vas deferens, and the residual mesonephric tubules form the efferent ducts. Non-pathological specimens of men within their reproductive years are understandably difficult to obtain, and even when such epididymides are made available, they often lack the proper preservation for good biological studies. It is well established that mammalian sperm, in general, mature in the epididymis, and the changes that occur in sperm during maturation have been recently reviewed. The propelling forces for sperm transport through the epididymis are: hydrostatic pressure from fluid secretion in the testis, and peristaltic contractions of the tubule. The bulbourethral glands are encased in the urogenital diaphragm. The bulbourethral gland secretion forms the first part of the ejaculate, or the pre-ejaculate, and serves to flush the tract with a buffered lubricant prior to the transport of sperm.