22 TADACHIKA MINOURA 



left gonad. Wolffian ducts of male type; miillerian ducts present 

 on both sides. The left miillerian duct is about 20 mm. long; 

 right about 9 mm., the anterior part of the right duct having 

 disappeared as in the female. The posterior portions of both 

 ducts are distinctly expanded; the expanded portions of the left 

 duct measures 7 x 1.5 mm., that of the right duct, 5 x 1.2 mm. 

 The ostium of the left duct and the differentiation of its posterior 

 part into uterus and shell gland are nearly the same as in the 

 normal female. But at least two parts, the one near the posterior 

 end of the left wolffian body and the other about 3 to 4 mm. 

 anterior to the expanded portion, show slight signs of degen- 

 eration ; that is to say, decrease in diameter of the duct. It is 

 evident, then, that this embryo possesses miillerian ducts of the 

 female type but gonads of the male type. It is therefore in a 

 typical intersexual condition. 



2. Embryo no. 31-3 (fig. 13, 14). Operated June 14, 1918. 

 Both testes (left 3.8 mm. long, right 4 mm. long) of a two-weeks- 

 old chick were grafted on the membranes of an embryo of eight 

 and one-half days' age. Opened Jane 24th. The two grafts 

 were found with vascular connections. Age of the embryo, 

 nearly 19 days; duration of graft, 10 days. 



Result : Gonads of the male type, both 3.5 mm. long. Miiller- 

 ian ducts present on both sides, the left one 22 mm., the right 

 one 20 mm., in length; posterior portions of both show signs of 

 enlargement. The right duct gradually increases in size posteri- 

 orly and the left one shows marked posterior differentiation. A 

 short middle portion of the left duct exhibits signs of degen- 

 eration. This embryo, like the preceding one, has gonads of the 

 male type, but the general condition of the miillerian ducts is 

 decidedly female-like, although not so strikingly so as in the 

 preceding case. 



Attention may be called to the fact that in these two embryos, 

 nos. 27-6 and 31-3, which are the most highly modified ones 

 obtained, the gonad graft was implanted on the embryo when 

 the latter was in a relatively early stage of sex differentiation. 



3. Embryo no. 47-10 (fig. 15). Operated July 19, 1919. 

 Two pieces of testis from a week-old chick were grafted on an 



