EEPROD UCTION. 649 



Near the posterior side of the testis the tubules unite to form 

 about 20 vasa recta (#), and these pass out of the gland at its 

 upper end, as the vasa efferentia (d), which become coiled up 

 into conical masses, the coni vasculosi; these, when unrolled, 

 are tubes from 15 to 20 cm. (6-8 inches) in length; they taper 

 somewhat from their commencements at the vasa efferentia, 

 where they are 0.5 mm. (-$ inch) in diameter, to the other 

 end where they terminate in the epididymis (e, e, Fig. 185). 

 The latter is a narrow mass, slightly longer than the testicle, 

 which lies along the posterior side of that organ, near the lower 

 end of which it passes (g) into the vas defer ens , h. If the 

 epididymis be carefully unravelled it is found to consist of a 

 tube about 6 metres (20 feet) in length, and varying in diam- 

 eter from 0.35 to 0.25 mm. ( T ^ to -fa inch). 



The vas deferens (A, Fig. 185) commences at the lower 

 part of the epididymis as a coiled tube, but it soon ceases to be 

 convoluted and passes up beneath the skin covering the inner 

 part of the groin, till it gets above the pelvis and then, passing 

 through the abdominal walls, turns inwards, backwards, and 

 downwards, to the under side of the urinary bladder, where it 

 joins the duct of the seminal vesicle; it is about 0.6 meters 

 (2 feet) in length and 2.5 mm. (fa inch) in diameter. Its 

 lining epithelium is ciliated. 



The vesiculcB seminales, two in number, are membranous 

 receptacles which lie, one on each side, beneath the bladder, 

 between it and the rectum. They are commonly about 5 cm. 

 (3 inches) long and a little more than a centimetre wide (or 

 about 0.5 inch) at their broadest part. The narrowed end of 

 each enters the vas deferens on its own- side, the tube formed 

 by the union being the ejaculatory duct, which, after a course 

 of about an inch, enters the urethra near the neck of the 

 bladder. In some animals the vesiculce seminales form a liquid 

 Avhieh IP added to the secretion of the testis. In man they 

 appear to be merely reservoirs in which the semen collects. 



The prostate gland is a dense body, about the size of a 

 large chestnut, which surrounds the commencement of the 

 urethra; the ejaculatory ducts pass through it. It is largely 

 made up of fibrous and unstriped muscular tissues, but con- 

 tains also a number of small secreting saccules whose ducts 

 open into the urethra. The prostatic secretion though small 

 in amount would appear to be of importance: at least the 

 gland remains undeveloped in persons who have been castrated 



