SEXUAL CHARACTERS OF SOME DOMESTIC BIRDS. 43 



drakes, the penis has always been found, sometimes rather smaller 

 and more flaccid than usual, but otherwise essentially the same as that 

 of an intact drake. 



In the castrated female the oviduct has always been found. It is 

 larger than that of the young chick, corresponding in its dimensions to 

 the increased size of the bird, but otherwise is entirely infantile. In 

 this respect it is like the comb of the capon. The increase in absolute 

 size of oviduct is mainly in length, with a slight increase in width, quite 

 like that of a young pullet prior to the enlargement of the oviduct in 

 anticipation of laying. 



EFFECT ON THE BURSA FABRICII. 



This is not a secondary sexual character, but like the thymus is 

 essentially an organ of the young and undergoes involution at or near 

 maturity. As slight attention was paid to it until its persistence was 

 noticed in two completely castrated drakes, little can be said of it now. 

 In incompletely castrated males it can not be found. Future observa- 

 tions may show that some intimate relation exists between it and the 

 primary organs of reproduction. 



OCCURRENCE OF CHARACTERS OF ONE SEX IN INDIVIDUALS OF 

 THE OPPOSITE SEX THAT ARE OTHERWISE NORMAL. 



MALE CHARACTERS IN THE OTHERWISE NORMAL FEMALE. 



The most conspicuous of these characters are spurs which occur in 

 some females that otherwise are apparently normal. In plate vii, B, 

 are shown the shanks of a White Leghorn hen now 8 years old. The 

 spurs, while somewhat more slender than those of a cock, i. e., in 

 proportion to her shanks, are otherwise quite as male-like as could be 

 wished. In other respects the bird is entirely female in character, even 

 her head furnishings being feminine. She has laid well and her eggs 

 have hatched well. This bird was about 2 years old when the spurs 

 were first noticed. At that time they were as well developed as in 

 cocks of the same age. Another hen. No. 1055, related to the first, 

 also has a fine pair of spurs. They appeared when the bird was 6 

 months of age as blunt stubs exactly like those of a cockerel, and by 

 the time she was a year old they had enlarged and become as pointed as 

 those of any male of the same age. Both these birds have been bred 

 from, and a hundred or more chicks hatched, but because of certain 

 circumstances few of the pullets have been kept sufficiently long to 

 develop spurs and these appeared in only one of the few kept. But 

 the fact that spurred females appear in large numbers in some strains 

 indicates that, at bottom, the spurs in the uncastrated female depend 

 upon some hereditary factor or combination of factors. 



The comb and wattles of some females are often very large, giving 

 the bird a masculine appearance. In Leghorns and other large-combed 

 breeds the large combs in the female are not considered mascufine, 



