13 



ined the contents of the tail of the epididymis of the bull, rabbit, 

 and guinea pig, finding full motility in each case, though the dura- 

 tion is not nearly as long as when the sperms are ejaculated in the 

 semen. 



The Vas Deferens is quite narrow (2 mm.) and runs from the 

 tail of the epididymis to the verumontanum, or colliculus semin- 

 alis, w'here it empties into the urethra in common with the duct of 

 the vesicle. At first it is lined by epithelium similar to that of the 

 vas epididymis, but this changes over into a peculiar low stratified 

 type. Ellenberger describes it as follows: " The epithelium 

 shows a very pronounced basal coat. The overlying cell zone 

 shows more (at the most, three) rows lying over each other of 

 elongated nuclei, while an outline of cell form is not ordinarily 

 noticeable, so that it may be spoken of as a syncitium, and at the 

 same time as a many layered epithelium." The mucosa forms low, 

 broad folds into the lumen. The tunica propria is a thin con- 

 nective tissue layer. The submucosa consists of thin connective 

 tissue. Three muscular coats are present : an inner thin longitud- 

 inal layer, middle circular layer, and an outer longitudinal layer. 

 All are more or less intimately blended, and are surrounded by 

 the adventitia, made up of connective tissue, elastic fibres and 

 scattered longitudinal muscle cells of the internal cremaster mus- 

 cle. Near the dorsal siu*face of the bladder, the ducts come in 

 close apposition, and for ten to twelve centimeters dilate to form 

 the ampullae. Here the mucous membrane bcomes much plicated, 

 forming long folds which anastomose freely. The function of the 

 vas is to convey the spermatozoa and secretions from the epididymis 

 to the urethra. Disselhorst (26) believes the ampulla acts "as a 

 seminal reservoir and states that he has found spermatozoa stored 

 up in the little pockets in the walls of this structure in animals 

 during the rutting time. He suggests, further, that there is a 

 relation between the state of development of the ampulla and the 

 time occupied by copulation. When the organ is small or absent, 

 as in dogs, cats, and boars, the coition is a slow process, but when 

 the ampulla is large and well developed, as in horses and sheep, 

 the coitus requires a relatively short time. Inasmuch as coitus is 

 so rapid in the bull, and the ampulla is so well developed, it seems 

 as though this function is very probable. 



The Seminal Vesicles are very compact glandular structures 

 ^ylng on either side of the median line, on the dorsal side of the 

 'ladder, and ventral to the rectum. In the mature bull they 

 rlieasure ten to twelve centimeters in length, four centimeters in 

 width, and about two and one-half to three centimeters in thick- 

 ness. The glands are distinctly lobulated. quite tortuous, and are 

 often asymmetrical in size and shape. They converge posteriorly, 

 to empty into the urethra at the colliculus seminalis with the 

 ampulla, in a slightly oval slit in the mucosa. IMicroscopically, 

 the gland is of the anastomosing tubular type, with very poorly 



