388 THE MALE REPRODUCTIVE ORGANS 



nar type and usually contains but a single layer of cells. Occa- 

 sionally basal cells are also found in the deeper part of the epithe- 

 lial layer ; in such case the epithelium may be said to be of the 

 pseudo-stratified type. This variation may possibly be partly de- 

 pendent upon the distention or relaxation of the vesicles. The 

 cells of the epithelium contain peculiar granules of yellowish pig- 

 ment which are present in considerable numbers and are quite 

 characteristic of the organ. The superficial cells appear to be 

 readily desquamated, and together with coarse granules of secre- 

 tion form the chief contents of the lumen. Occasional small con- 

 cretions of irregular form, and homogeneous or lamellar struc- 

 ture, similar to those of the prostate gland, are also found. The 

 seminal vesicles usually contain but few spermatozoa. Occasion- 

 ally these are present in larger numbers ; at other times they may 

 be entirely absent. 



THE EJACULATOBY DUCTS 



These ducts are formed by the union of the ampullae of the 

 vasa deferentia and the ducts of the seminal vesicles and are simi- 

 lar in structure to the ampullae of which they are the continuation. 

 The ejaculatory ducts, however, possess a thinner wall and their 

 mucosa presents the same folded condition as in the seminal vesi- 

 cles, but to a lesser degree. In its prostatic portion the muscula- 

 ture of the vas deferens blends with the muscular stroma of the 

 prostate, so that in the ejaculatory duct the smooth muscle no 

 longer forms a distinctly lamellated coat. On approaching the 

 urethra, the epithelium of the ejaculatory ducts presents a gradual 

 transition to the stratified epithelium of the urethral canal. 



THE PROSTATE GLAND 



This is a compound tubulo-alveolar gland which pours its 

 serous secretion into the neighboring portion of the urethra by 

 means of two large and many small ducts. These open either 

 directly into the urethral canal or indirectly through the utriculus 

 prostaticus (sinus pocularis). The secreting alveoli are embedded 

 in a very dense fibro-muscular stroma which, at the surface of the 

 organ, forms an unusually thick capsule in which interlacing bun- 

 dles of smooth muscle are most prominent. This portion of the 

 sfcroma also contains intrinsic striated muscle fibres in limited 

 numbers. Broad bands of fibro-muscular tissue pass inward from 

 the capsule and form a network of thick septa in the meshes of 



