244 SPECIAL ANATOMY. 



superior border of the testicle, externally by a kind of mesentery, 

 lig. epididymidis s. mesorchium, and internally it is covered 

 higher up. 



The development of the vaginal membrane into a closed sac is 

 closely connected with the descent of the testicle. 



Descensus testiculi. In the tenth to twelfth week of foetal life we see a 

 small elongated testicle, in a mesentery which passes off from the peritonaeum 

 of the posterior abdominal wall, below the kidney. In the fissure which 

 leads to it from the posterior abdominal wall, the vasa testiculi are situated, 

 in the centre the vas deferens, below, a fibrous thicker cord projects from it 

 into the short straight inguinal canal. 



The leading string, gubernaculum Hunteri, which is widely fixed to the 

 Scrotum. The testicle increases by degrees, not so the gubernaculum, which 

 becomes shortened in proportion to the other parts, and draws down the 

 testicle out of the mesenteric fold, so that the immediately investing and 

 closely attached portion, only (the subsequent tun. serosa testis) , of the testicle, 

 accompanies it. 



In its passage through the inguinal canal, the testicle draws down with it 

 that portion of the peritonaeum which is connected with its covering a cavity 

 appears therefore inside the scrotum, on the external surface of which the 

 testicle, with its vessels, &c., is situated, and which is separated from the 

 cavity of the peritoneum by a constriction only, the vaginal canal, canalis 

 vaginalis. (Intestines pass through this canal, in hernia congenita ; thus they 

 are only separated from the Parenchyma of the testicle [the tunica albuginea~\ 

 by the serous investment of each other, whilst in hernia acquesita, two folds of 

 peritonceum, namely, the hernial sac and tunica vaginalis testis [reflexa'], lie 

 there between them). 



So soon as the testicle has arrived at the fundus of the scrotum, the obli- 

 teration of the vaginal canal commences, as the tunica becomes converted into 

 a ligamentous band of uniting tissue, habercula, between the internal inguinal 

 ring and the superior extremity of the testicle. 



These filaments even sometimes disappear. The obliteration commences 

 above or below, or from both points at the same time, towards the termination 

 of foetal life ; at birth the canal is frequently open, and intestines fall into it, 

 forming a hernia (hernia inguinalis congenita). Serum collecting in it forms 

 a Hydrocele. 



478. 3. The vas s. ductus defer ens, 



the continuation of the epididymis, commences at the cauda of 

 the last, ascends through the inguinal canal, together with the 

 remaining parts of the spermatic cord into the abdomen, and 

 terminates before the vesiculss seminales, associated with the 

 excretory duct, of which it forms the ductus ejaculatorius. In 

 its course we distinguish four parts. 



a. Pars testicularis passes in a serpentine form from behind 

 forwards and from below upwards along the inner side of the art. 

 ven. and spermatica and the epididymis. 



b. Pars funicularis, ascends in a proper sheath behind art. 

 and ven. spermat., directly as far as the inguinal canal, inside of 

 the spermatic cord. 



