THE TESTICLES 



1029 



in fnjut of the external iliac vein, enters the i)elvis (pelvic stage) close to the ilio- 

 pubic suture, and runs downwards and backwards over the side of the bladder, 

 crossing it on the vesical side of the oljliterated hypogastric artery and ureter, to 

 reach the side of the posterior wall of the viscus. Here it lies between tlie bladder 

 and the second stage of the rectum, and, becoming enlarged and sacculated, j)asses 

 downwards and inwards towards the base of the prostate, where it narrows and is 

 joined by tlie lower end of the vesicula seniinalis. The common tube descends as 

 the ejaculatory duct, to pierce the prostatic fissure and open into tlie prostatic 

 ])ortion of the urethra. The two vasa deferentia, where they lie in front of the 

 rectum, are separated by a triangular interval, the apex of which is formed by the 

 ap})roximation of the ejaculatory ducts, and lies immediately above the ])rostate. 

 The wliole of the pelvic portion of the vas is subperitoneal except near its termina- 

 tion, where it is invested only by recto- vesical fascia and an extension of subperi- 

 toneal tissue. 



Fig. 625.— Vas Deferens and "Vesicula Semixalis dissected. (After Sappey.) 



SACCULI Of AMPULU OF VAS 



SACCULUS 



JUNCTION OF VAS AND VESICULA 

 EJAGUUTORY DUCT 



The entire length of the vas deferens averages about sixteen inches (40 cm.), of 

 which an inch and a quarter (3 cm.) may be allotted to the testicular stage, three 

 inches to the funicular stage, an inch and three-quarters to the inguinal stage, and 

 the rest to the pelvic stage. It is cylindrical and of uniform diameter (about one- 

 tenth of an inch) in its funicular, inguinal, and })elvic stages down to the retrovesical 

 portion, and its walls are of great thickness, about one-twenty-fifth of an inch 

 (1 mm. ), while its calibre is extremely small. It is here composed of an outer cellu- 

 lar coat containing vessels and smooth muscular fibres, a threefold muscular coat 

 with external and internal longitudinal and middle circular layers, and a mucous 

 membrane lined with cylindrical ei)itlu'lium. The am]>ullated retrovesical ])ortion 

 differs from the rest in the thinness of its walls and in its sacculation, and in these 

 resp<'cts approximates to the vesicuhe seminales (fig. G25). 



The VESlCULiE SEMINALES are two diverticular reservoirs situated between 

 the bladder and rectum external to the anipulhe of the vasa deferentia. 



