SEXUAL CHARACTERS OF SOME DOMESTIC BIRDS. 17 



approaching more closely to the female than to the male in general 

 color. However, since her feather coloring resembles neither the nor- 

 mal female nor the male in breeding plumage, it is perhaps better to 

 consider this bird as a distinct type, designated below as Type II 

 (plate iv). The majority of her individual feathers are either male or 

 female in character and not a mixture of the two. The plumage as a 

 whole, however, is a mixture, containing typical male and female 

 feathers, plus a third type that is neither. The latter are brown and 

 buff, but are barred transversely, either in a perfect or more or less 

 broken pattern (plate vi, figs, r and q) . On the ventral surface some 

 feathers are more or less intermediate — i. e., each feather shows both 

 male and female characters. On the whole the condition approaches 

 most nearly to that of the male in his summer plumage, but differs 

 enough so that it can not be said that it is such a plumage, especially 

 in this individual, which is very much more like an unaltered female 

 than the bird figured. Further, this plumage is maintained through- 

 out the year. 



No. 116, a pure-bred Rouen, belongs to the same type as No. 4. 

 Hatched May 18, 1912, the ovary was removed August 7, 1912, the 

 removal being complete as far as an examination with the naked eye 

 could determine. She was examined from time to time and no male 

 feathers were found as late as September 7. Accordingly, the bird was 

 opened and a careful examination made of the left side. No trace of 

 any ovarian material could be found. The lack of male feathers a 

 month after the operation was probably due to the fact that it was not 

 ready to exchange the juvenile coat for the adult. Thus the feathers 

 regenerating from follicles emptied at the time of operation belonged to 

 the juvenile plumage. By October 26 the juvenile had been replaced 

 by the adult plumage, which belonged to the type described for No. 4. 

 The further history of the case is complicated by an attempt to engraft 

 bits of ovary beneath the skin. Apparently, however, the implanted 

 ovary was without influence, for feathers plucked at the time were 

 replaced a month later by either typical male feathers or those of 

 Type II. For a time the bird was not under observation, but in the 

 spring of 1913 she had not changed in any essential. This condition 

 was maintained throughout the summer, until the fall molt took place, 

 when to my surprise she developed a much more perfect male coat, 

 corresponding closely to that shown in plate iv, which is a figure of 

 No. 24 described in an earlier paper. A discussion of this type will be 

 taken up in a later section. 



Female Ducks Partially Ovariotomized. 



We may now turn our attention to some of the cases in which the 

 removal of the ovary was almost but not quite complete. These cases 

 throw considerable light on the effects of removal, besides giving us a 

 more precise knowledge of the action of the ovarian secretion. 



