124 BENJAMIN H. WILLIER 



SUMMARY 



1. In the free-martin an indifferent gonad with a primary 

 female determination transforms in the male direction under 

 the influence of male sex hormones. 



2. Three distinct steps may be recognized, which may be 

 characterized as low, medium and high degrees of transformation 

 in the male direction. These three groups constitute a chain 

 of connecting links between an embryonic ovary and a testis. 



Such a graded series of transformations is evidenced as follows : 

 a. The sexual cords exhibit a series of gradations between 

 medullary cords and seminiferous tubules. 



6. The interstitial cells increase in number as the gonad trans- 

 forms in the male direction. 



c. The rete transforms in the male direction by developing 

 connections (tubuli recti) between the rete tubules and the semi- 

 niferous tubules, and by connections between the rete tubules 

 and the epididymal tubules. Such connections are not made 

 in the gonad exhibiting a low degree of transformation. In the 

 group of moderately transformed gonads a few such connections 

 are made, while in the most highly transformed gonads such 

 connections are numerous. 



The distance that the rete penetrates into the sex-cord region 

 varies according to the degree of transformation of the gonad. 

 In the most highly transformed gonad it penetrates to the poste- 

 rior end of the sex-cord region, as in the normal testis. 



The rete becomes less eccentrically located with reference 

 to the sex-cord region in cases of pronounced male organization. 

 It is never centrally placed as in the normal testis. 



d. The epididymis is absent from gonads exhibiting a low 

 degree of transformation; only the head of the epididymis is 

 present in gonads showing a moderate degree of transformation, 

 while a typical epididymis is present in the most highly trans- 

 formed sex glands. 



e. The distribution of the blood-vessels correspondingly 

 ranges from a typical ovarian arrangement to a typical male 

 arrangement. 



