894 



THE DEVELOPING ENDOCRINE GLANDS 



Two sets of primitive ducts thus are established in the majority of verte- 

 brates in each sex, the Miillerian or female duct and the mesonephric (pro- 

 nephric) or male duct. 



During later normal development, the Miillerian duct is developed in the 

 female, while, in the male, the mesonephric duct is retained and elaborated 

 as the functional, male reproductive duct. 



The male duct system is dependent upon secretions from the developing 

 testis for its realization during the later embryonic period and during post- 

 natal development, whereas the female duct develops independently of the 

 ovary up to the time of sexual maturity when its behavior is altered greatly 

 by the presence of the ovarian hormones. 



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