386 



EMBRYOLOGY. 



part in the development of the female and male sexual organs the 

 inguinal ligament of the primitive kidney. It subsequently becomes 

 in man the gubernaculum Hunteri, in woman the round ligament of 

 the uterus (ligamentum teres uteri}. 



On the median side of the primitive kidney is found either the 



testis or the ovary (kd), 

 according to the sex of 

 the embryo, both sexual 

 organs still being at this 

 time small oval bodies. 

 They also possess me- 

 senteries of their own, 

 a mesorchium or meso- 

 varium, by means of 

 which they are con- 

 nected with the root of 

 the primitive kidney. 

 As long as the sexual 

 organs retain their posi- 

 tions on each side of 

 the lumbar vertebrae, 

 the blood-vessels that 

 supply them run in an 

 exactly transverse direc- 

 tion : the arteria sper- 

 matica from the aorta 

 to the ovary or the 

 testis, the vena sperma- 

 tica from the gland to 

 the vena cava inferior. 



The various efferent 

 ducts lie at this time 

 close together at the 

 margin of the mesone- 

 phric fold (fig. 219), the 

 most anterior [ventral] being the Miillerian duct (mg). Farther back- 

 wards toward the pelvis the ducts of both sides approach the median 

 plane (fig. 219), whereby the Miillerian duct (mg) comes to lie for a 

 certain distance on the median side of and then behind [dorsal of] 

 the mesonephric duct (ug), so that altogether it describes around the 

 latter a kind of spiral course. When they reach the lesser pelvis, 



cl' 



Tig. 219. Diagram of the indifferent fundament of the 

 urogenital system of a Mammal at an early stage. 



n, Kidney ; kd, sexual gland ; un, primitive kidney ; ug, 

 mesonephric duct ; mg, Miillerian duct ; ntf, its an- 

 terior end ; gh, gubernaculum Hunteri (mesonephric 

 inguinal ligament) ; hi, ureter ; hi', its opening into 

 the urinary bladder ; ug", mg", openings of the mesone- 

 phric and Mullerian ducts into the sinus urogenitalis 

 (sug) ; md, rectum ; cl, cloaca ; ghS, sexual eminence ; 

 gw, sexual ridges ; cl', external orifice of the cloaca ; 

 hbl, urinary bladder ; hbl', its elongation into the 

 urachus (the future lig. vesico-umbilicale). 



