586 



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 rovmd 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 vertebrse, . 

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

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



Fig. 219. — Diagram of the indifferent fundament of the 

 urogenital system of a ISammal at an early stage. 



■^^, Kidney ; kd, sexual gland ; un, primitive kidney ; ug, 

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

 terior end ; gh, gubernaculum Hunteri (mesonephrio 

 inguinal ligament) ; hi, ureter ; M', its opening Into 

 the urinary bladder ; u^', mg", openings of the mesone- 

 phrio and Miillerian ducts into the sinus urogenitalis 

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

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

 hbt, uiinaiy bladder ; kbl', its elongation into the 

 urachus (the future lig. Yesico-umbilicale). 



