478 • CATHARINE LINES CHAPIN 



The medullary region in this free-martin is relatively larger 

 than in the other free-martins studied, and more organized. 

 Almost the entire region is differentiated into sex cords, sepa- 

 rated by connective tissue stroma. Some of these sex cords 

 resemble the seminiferous tubules, as do a few sex cords in free- 

 martin T2; others resemble the medullary cords. Degenerating 

 follicles are found but no germ cells. Interstitial cells have not 

 been identified in the stroma. The superficial peritoneum and 

 albuginea are like those structures in the male. Again there is 

 complete absence of cortex. The rete resembles the rete testis 

 in structure, relative size and distance of penetration into the 

 gonad, but, lying at one side of the sex cord region, near the 

 mesentery, it resembles the rete ovarii in respect to its location. 

 There is a large amount of rete anterior to the gonad in the 

 position which, in the male, is occupied by the epididymis. 

 This resemblance to the epididymis is still more marked because 

 in the region where the vas epididymis leads from the vasa 

 efferentia into the vas deferens, are rudiments of three ducts. 

 These ducts are lined with ciliated epithelium but are closed at 

 both ends and, although the walls of tubules from the rete come 

 in contact with the walls of these ducts, in no place do they 

 actually open into each other. However, this mass of rete, 

 which resembles epididymis in position does not resemble it in 

 structure, being, in that respect like the typical rete testis. 



The Wolffian body has degenerated, but lateral to the gonad are 

 many tubules. Among other structures are found large blood 

 vessels like those of male T4 (fig. 9). 



Summary. The free-martin T42 resembles the male in ab- 

 sence of cortex, presence of albuginea, structure of the super- 

 ficial peritoneum, and structure of the rete. Some of the sex 

 cords are like medullary cords ; others are like the seminiferous 

 tubules. The position of the rete in the free-martin is that of the 

 rete ovarii. 



