HOMOLOGY. 89 



Bantam, in which the cocks do not possess either 

 combs, or long tail-feathers. The breed is very 

 infertile, but has been perpetuated for more than 

 seventy years. An extraordinary case has been 

 recorded of an old hen of this breed whose 

 ovaries became diseased, when she assumed all 

 the external characters of a fully developed 

 cock; characters which had lain latent in both 

 sexes of the breed for sixty years ! 



The most constant secondary sexual organs in 

 mammalia are the mammas, which are in most 

 cases fully developed only in the adult female. 

 These organs are peculiar to the mammalia, the 

 nearest analogical approach to them in other 

 animals being perhaps in pigeons, whose crops 

 undergo a peculiar alteration in both sexes 

 during the breeding season, for the preparation 

 of the food of the young. In mammalia, the 

 mammas are present in both sexes, and in early 

 life are not more developed in one sex than in 

 the other, while their structure is identical in 

 both. They are very variable in development, 

 and although this is partly dependent on the 

 condition of the reproductive organs, it is by no 

 means wholly so; and apart from the fact of their 

 being often almost equally developed in both 



