SEXUAL CHARACTERS OF SOME DOMESTIC BIRDS. 



21 



have been found. It has seemed best, however, not to delay the rest 

 of the paper to complete the histological work, especially as similar 

 material has been found in castrated females (fowl) 1 and as a number of 

 the birds are still under observation. It seems probable that the body 

 found is the epididymis, which has developed in the absence of both 

 germ cells and supporting cells. 



DOMESTIC FOWL. 



The operations on fowl yield results similar to those from ducks. 

 The latter thus far have proved more suitable for experimentation 

 because of greater hardiness and freedom from diseases, at least in the 

 stocks available. Moreover, the ovary is removed more readily than 

 from chicks. For these reasons fewer cases are available for the fowls 

 than for ducks. 



TABLE 3. Ovariotomized female fowl. 



FEMALE FOWL COMPLETELY OVARIOTOMIZED. 



No. 4471- Hatched September 8, 1912. According to the protocol 

 made November 13, 1912, "a clean and complete removal of the ovary 

 was effected. " By November 26, male characters in the form of black 

 feathers were visible in the breast. These continued to increase in 



l Cf. Goodale, 1916. 



2 Male plumage. 



