THE FACTOKS OF EVOLUTION 145 



covered by a thick red growth of the cere ; in the bagadottes 

 it is crooked, like an awl. The beak of the turbit becomes, in 

 extreme cases, so short that the birds are no longer able to 

 feed themselves, but must be fed artificially. The pouter carries 

 its body upright. Its throat is of an enormous size, and the 

 bird is able to blow it out with air. The fantails possess, instead 

 of the normal number of twelve tail-feathers, thirty to forty, 

 which are carried upright spread out like a fan. Some pigeons 

 have smooth plumage, others rough ; some have a feather- 

 mantle or a cap, others a ' white beard ' or a ' shirt-collar.' 

 Further, the size of their body, the number and size of ribs and 

 tail-vertebrae, the formation of internal organs, differ widely 

 ia the different breeds. In the home of pigeon culture, England, 

 many breeders have attained such a state of skill that they are 

 able to inbreed to order, in a very short time, any desired feature. 

 It is even possible by breeding to alter mental qualities, i.e., the 

 delicate structure of the brain, as is proved, to mention only one 

 instance out of many, by the well-known tumblers. Fanciers 

 have succeeded to breed into this pigeon the habit of ascending 

 to a considerable height and then turning a complete somer- 

 sault or several somersaults in the course of their descent. A 

 similar phenomenon is observed in the Japanese dancing mice, 

 which will sometimes turn round for several minutes exactly like 

 a live spinning top. 



Let us now consider the question of the methods to be 

 adopted by a breeder in order to obtain a certain feature. Let 

 us suppose that he intends to breed a carrier-pigeon, that is, a 

 bird with an extreme growth of wattle round the bill and eyes. 

 A prize monstrosity such as this is pictured on the coloured 

 plate. First of all, the breeder will look around his stock 

 of pigeons, pick out those birds which either possess these 

 characteristics, or at least one of them, in a more pronounced 

 form than their companions and breed from them. As inborn 

 features are inherited, as the descendants are in a sense the 

 ' sum of both parents,' there will in most cases be found among 

 the young pigeons some birds which possess more strongly 

 developed wattles than their parents. These birds will now be 

 selected for further operations, and by carrying on this process 

 of selection for several generations the breeder will frequently 



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