REPRODUCTIVE SYSTEM OF FREE-MARTINS 481 



The Miillerian duct becomes irregular in young free-martin 

 embryos as in young males. In older free-martins the tube has 

 atrophied. The posterior enlargement may persist. This is 

 homologous with the uterus in the normal female and the uterus 

 masculinus or prostatic vesicle in the male. The two Miillerian 

 ducts unite in the female to form the body of the uterus. In thp 

 male they do not join. In only one free-martin were they found 

 to unite — T6 — and in that case the union was for a distance of 

 less than 2 mm. The failure of these ducts to unite to form the 

 body of .the uterus is in accord with Paton's'' finding of non- 

 development of the uterus in castrated female guinea pigs. In 

 two free-martins, 20 cm. T13 and 12.5 cm. T26, a rudiment of 

 the Miillerian duct is found near the anterior end of the gonad. 

 This is probably the homologue of the hydatid of Morgagni, a 

 vestige of the Miillerian duct which persists in that region in 

 the male. 



From the foregoing facts it is evident that, 1 . As a result of the 

 introduction of the interstitial secretion of the male, those organs 

 in the free-martin which are present in the indifferent stage, de- 

 velop toward the male condition (rete, first set sex cords, primary 

 albuginea), and those which develop in the normal female at sex 

 differentiation or later are inhibited from developing (cords of 

 Pfliiger, definitive albuginea, union of Miillerian ducts to form 

 uterus). 



2. The high degree of variation found in the organs of the re- 

 productive system in free-martins is indicative of the variability 

 of the time at which the interstitial secretion of the male embryo 

 may first be introduced into the circulation of the female embryo, 

 and the amount which may be introduced; in other words, the 

 variability of the time and degree of anastomosis of the extra 

 embryonal blood vessels of the two embryos. 



a. The fact that in some free-martins the Wolffian body and 

 Wolffian duct have degenerated more than in a male of corre- 

 sponding size, though not more than in the female, suggests a 

 later introduction of the secretion of the male, or the introduc- 



^ D. N. Paton, Regulators of Metabolism. 



