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HANDBOOK OF PHYSIOLOGY. 



before it enters the prostate gland, through part of which it passes to 

 terminate in the urethra, gives off a side branch, which bends back 

 from it at an acute angle : and this branch dilating, variously branching, 

 and pursuing in both itself and its branches a tortuous course, forms 

 the vesicula seminalis. 



Structure. Each vesicula may be unravelled into a single branching 

 tube sacculated, convoluted, and folded up. 



The structure resembles closely that of the vasa deferentia. The 

 mucous membrane, like that of the gall-bladder, is minutely wrinkled 

 and set with folds and ridges arranged so as to give it a finely reticu- 

 lated appearance. 



The Penis. The penis is composed of three long more or less 

 cylindrical masses, inclosed in remarkably firm fibrous sheaths, of 



Fig. 451. Dissection of the base of the bladder and prostate gland, showing the vesiculae 

 seminales and vasa deferentia. a, lower surface of the bladder at the place of reflection of the 

 peritoneum ; 6, the part above covered by the peritoneum ; -t, left vas deferens, ending in e, the 

 ejaculatory duct ; the vas deferens has been divided near t, and all except the vesical por- 

 tion has been taken away; s, left vesicula seminalis joining the same duct; s, s, the right vas 

 deferens and right vesicula seminalis, which has been unravelled ; p, under side of the prostate 

 gland; m, part of the urethra; u, u, the ureters (cut short), the right one turned aside. 

 (Haller. ) 



which two, the corpora cavernosa, are alike, and are firmly joined 

 together, and receive below and between them the third part, or corpus 

 spongiosum. The urethra passes through the corpus spongiosum. The 

 penis is attached to the symphysis pubis by its root. The enlarged ex- 

 tremity or glans penis is continuous with the corpus spongiosum. The 

 integument covering the penis forms a loose fold from the junction of 

 the glans with the body, called the prepuce or foreskin. 



