HORMONES IX DIFFERENTIATION OF SEX 



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Fig. 2.15. Sex transformation in the testis of the duck, isolated in vitro at the beginning 

 of sexual differentiation and cultured in close contact with an embryonic ovary (Wolff and 

 Haffen, 1952b). A. The ovary of such a combination, showing the thick covering germinal 

 epithelium and the vacuolated condition of the medullary region. This young ovary is es- 

 sentially normal in structure. B. Intersexual condition induced in the testis under the in- 

 fluence of the ovary. The heavy germinal epithelium representing the cortex is as well 

 developed as in a normal ovary ; the meduUaiy region retains largely the compact structure 

 of a testis, but signs of vacuolation are appearing. This gonad is an ovotestis. C and D 

 represent, respectively, the ovary and the completeh' transformed testis in another experi- 

 ment. The two gonads in this case show almost identical structure, featuring the thick cortex 

 and vacuolated medulla of an ovary. In these experiments the other testis, cultured alone, 

 developed normal testicular structure. (From Et. Wolff and K. Haffen, Arch. x\nat. microscop. 

 et Morphol. exper., 41, 184-207, 1952.) 



