DEVELOPMENT OF THE REPRODUCTIVE ORGANS. 



2043 



Suprarenal 

 body 



In the female the Wolffian tubules and duct play a subordinate role, remaining 

 to form rudimentary organs, the epoophoron (page 2000), the paroophoron (page 

 2002), and, when the Wolffian duct persists, the duct of Gartner (page 2001). The 

 broad ligament is formed by the enlargement of the primary peritoneal fold containing 

 the Miillerian and Wolffian ducts. 



Descent of the Ovary. — The primary position of the ovary, at the side of 

 the upper two lumbar vertebrae, corresponds with that of the testis, the sexual 

 gland, as in the male, undergoing migration in order to gain its permanent loca- 

 tion. In the case of the ovary, however, this migration is much more limited, 

 notwithstanding the provision of the same equipment for descent as in the male, in- 

 cluding the genito-inguinal ligament, inguinal bursa, peritoneal evagination, and even 

 cremaster muscle. The gland 



fails to reach the internal Fig. 1724. 



abdominal ring and remains 

 until birth at the brim of the 

 pelvis in consequence of the 

 large size of the uterus in 

 relation to the small pelvis. 

 When the growth and expan- 

 sion of the latter have pro- 

 vided additional capacity, as 

 the uterus sinks to its definite 

 position, the ovaries, attached 

 by their ligaments and ovi- 

 ducts, follow into the pelvis. 



The genito-inguinal liga- 

 ment becomes the round 

 ligament of the uterus, the 

 lower end of which is attached 

 to the subcutaneous tissue of 

 the labium majus at the exter- 

 nal abdominal ring. These 

 relations are foreshadowed by 

 the close association of the 

 lower end of the foetal liga- 

 ment to the bottom of the 

 inguinal bursa and the wall of 

 the processus vaginalis. The 

 lumen of the latter usually 

 disappears, but in exceptional 

 cases may persist as the canal 

 of Nuck (page 2015). Asso- 

 ciated with this condition, occasionally the ovary more closely imitates the descent 

 of the testicle by passing into or even through the inguinal canal. 



DEVELOPMENT OF THE EXTERNAL ORGANS. 



The external genital organs develop from an indifferent type and, until the 

 beginning of the third month, do not exhibit the distinguishing characteristics of 

 either sex. While the differentiation of the sexual glands occurs early, in embryos 

 of 22 mm. length, not until about the ninth week, in embryos of 31 mm., is sex 

 determinable by inspection of the external organs. The earliest trustworthy external 

 indication of sex is the downward curve of the growing genital tubercle, later the 

 clitoris, that takes place at this.time in the female (Herzog). 



About the fifth week, before the rupture of the cloacal membrane, the tissue 

 bordering the external cloacal fossa in front grows forward into a rounded projection, 

 the genital tubercle. The latter rapidly increases in size and differentiates into a distal 

 knob-like end and a bulbous ventral expansion at its base which becomes divided 

 by a groove that extends along the under surface of the genital tubercle. The lips 

 of this groove elongate into \h^ genital folds that lie on either side of tjie opening into 



Suprarenal 

 body 



Kidney 



Ureter 



Oviduct 

 Round 

 ligament 



Bladder 



Hypogas- 

 tric artery 



Sexual organs of female foetus of third month, showing ovaries 

 still undescended and bicornate uterus. X 2. 



