104 THE ORIGIN OF GYNANDROMORPHS. 



is very similar to the normal cock. The comb and wattles, however, 

 are greatly reduced in size and have a pale color, being relatively 

 deficient in blood. The influence of castration on the spurs is not clear, 

 for they may be well developed in the capon and even in the hen. 

 The influence of the ovary on the plumage of the hen has long been 

 suspected to be important. Old hens in which the ovary had ceased 

 to function were known to develop cock feathering, and the same 

 result was said to follow if the ovary became diseased. But much 

 uncertainty existed in regard to this evidence until Goodale, by care- 

 fully planned and thorough work, showed that when the ovary was 

 removed from young birds they developed the complete plumage of 

 the male. In the race of Leghorns the cock is red with plumage like 

 that of the wild Gallus hankiva; the hens are brown. After spaying, 

 the hens develop the complete male plumage. The spurs develop more 

 fully than in the normal female of the Leghorn race. 



When pieces of the ovary of a Leghorn hen were inserted in the 

 body-cavity of a Leghorn capon, the latter developed only the female 

 plumage. 



In domesticated ducks (Rouen and Mallard) there are two molts. 

 The drake molts in June and assumes his summer plumage, which is 

 more like that of the female than is his other so-called nuptial plumage. 

 The nuptial plumage develops during the autumn molt. If the testes 

 are completely removed after the autumn molt the male retains his 

 nuptial plumage even through the summer molt. Goodale finds that 

 in normal birds, when the summer plumage reaches its highest stage 

 of development, sexual activity diminishes or disappears, and few or 

 no sperms are present. It is at this time then that the drake de- 

 velops his nuptial plumage, as removal of feathers shows In other 

 words, it is the summer plumage (the one that is more like the female) 

 that develops when the sexual organs are at the highest development, 

 while the nuptial plumage develops when the sperms are not being 

 produced in the testes. It appears, then, that the nuptial plumage 

 is not influenced by the testicular condition, while the female-like 

 plumage may possibly be due to the inhibitory eff'ects of the testicular 

 secretions. In other words, the case is somewhat like that of the 

 Sebright, in which the presence of the active testis suppresses the 

 potential cock feathering of the male. 



These results do not appear to furnish any solution of the problem 

 of bilateral gynandromorphs in birds, because the chief difficulty 

 remains so long as any internal secretion, whether ovarian or testicular, 

 determines in an individual the character of its plumage. Any theory 

 of bilateral gynandromorphs in birds must be prepared to offer some 

 explanation as to why the ovarian extracts do not suppress in them 

 the male feathering on the male side. Two more or less plausible 

 answers can be given at present. One of them is that in certain 



