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SEXUAL DIMORPHISM 



that by breeding one stock for one character and another 

 for another, without crossing the stocks, two distinct breeds 

 or varieties may be produced. I also admit that variations 

 in domesticated animals occur spontaneously, i.e. apparently 

 without relation to special conditions of life. The question 

 here, however, is whether variations occur spontaneously 

 under domestication which are in all respects similar to the 

 secondary sexual characters so common in nature. 



The chief peculiarities of the Carrier breed are the beak- 

 wattle and the eye -wattle, the former a large wrinkled 

 excrescence of bare skin and tissue around the base of the 

 beak, the latter a flat circular expansion of similar skin, not 

 much projecting, around the eye. Now these peculiarities 

 are not confined to the male bird. I rely for the evidence 

 I am about to use on the Booh of Pigeons by Eobert Fulton, 

 edited by Lewis Wright, and published by Cassell and Co. 

 The hen at four years of age has in some individuals almost 

 as large a beak-wattle as the cock at the age of three years 

 when the latter is fully developed. Still there is a certain 

 inferiority of development of the beak- wattle in the hen 

 as a general rule. In the eye-wattle there seems to be 

 scarcely any difference between the sexes. 



The beak- wattle begins to "break out" at the age of 

 nine or ten months. This does not mean that it is entirely 

 absent before that time, but that it begins to show the 

 bulbous protuberances at that period. Now of course the 

 wattles are not entirely new structures in the Carrier. In 

 the wild original the skin at the base of the beak over the 

 nostrils is naked, scaly and protuberant, and there is some 

 naked skin around the eye. The wattles of the perfect fancy 

 Carrier are only produced by the hypertrophy or excessive 

 growth of these parts of skin. 



In the book to which I have referred it is stated that 

 the Carrier variety is more quarrelsome and spiteful than 



