390 



EMBRYOLOGY. 



The non-stalked hydatid (hy) is developed out of the other end 

 of the Mullerian duct. It is a small vesicle that rests upon the 

 epididymis, is lined with ciliate cylindrical epithelium, and is continued 

 into a small, likewise ciliate canal. At one place it possesses a funnel- 

 shaped opening, which has been compared by Waldeyer to the 

 pavilion of a Fallopian tube in miniature. 



In order to complete the account of the development of the sexual 

 organs, there still remain to be m^entioned the important clianges 

 f position which the testis together with the attached rudiments 

 undergoes. Since early times, these have been embraced under the 

 Tiame of descensus testiculorum. 



Originally the testes (fig. 222 h) lie, as previously stated, in the 



peritoneal cavity at 

 the side of the lumbar 

 vertebrK. In the 

 third month we find 

 them already in the 

 greater (false) pelvis^ 

 in the fifth and sixth 

 on the inner side of 

 the anterior wall of 

 the abdomen close to 

 the inner abdominal 

 ring (fig. 223). In 

 consequence of these 

 changes the nourish- 

 ing blood - vessels; 

 ■yhich at first ran transversely, have altered their direction and now 

 pass obliquely from below upward, because their original place of 

 attachment to the abdominal aorta and the inferior vena cava 

 remains the same. How is the migration to be explained ? 



I have already mentioned the inguinal ligament, or the guberna- 

 culum Hunteri (fig. 222 and 223 gh), which puts the primitive 

 kidney, or, when this has disappeared, the testis, into connection with 

 the inguinal region. This Ugament has in the meantime become a 

 strong connective-tissue cord, in which non-striate muscles also lie. 

 Its upper end is attached to the head of the epididymis (nh) ; its 

 lower end traverses the abdominal wall to be inserted into the 

 corium of the inguinal region. Apparently this gubernaeulum plays 

 a part in the migration of the sexual organs. Formerly it was be- 

 lieved that it exercised a traction upon the testis, in which connection. 



Kg. 2I!3.— Human embryo of the fifth month, after Brauakit. 



Natural size. 

 md, Rectum ; h, testis ; nh, epididymis ; si, vaa deferens ; gh, 



gubernaeulum Hunteri with processus vaginalis peritonei ; 



J>1, bladder with lig. vesico-umbiUcale medium. 



