THE DARWINIAN THEOKY 37 



as well as of some other breeds, which suggests the arrangement of 

 feathers on a wing. 



Furthermore, the number and size of wing and tail-feathers in 

 the different breeds often deviate considerably from the normal. 

 The fantail (No. 7) in its most perfect form possesses forty tail- 

 feathers, instead of the twelve usual in the wild rock-pigeon, and they 

 are carried upright like a fan, while the head and neck of the bird are 

 bent sharply backwards. In the hen-like pigeons the tail-feathers 

 are few and short, so that they show an upright tail like that of a hen. 

 I have already referred to the extraordinary carunculated skin-growth 

 on the bill of many breeds : such folds also often surround the eye, 

 and, as in the Indian barb (No. 2), are developed into well-formed thick 

 circular ridges, while in the English carrier (No. 6) they lie about the 

 bill as a formless mass of flesh. 



Even the skull has undergone many variations, as can be 

 observed even in the living bird in many of the breeds with short 

 forehead. Differences are to be found, too, in the number and breadth 

 of the ribs, the length of the breast-bone, the number and size of the 

 tail-vertebrse in different breeds. Of the internal organs, the crop in 

 many breeds, but particularly in the pouters (No. 1 ), has attained an 

 enormous size, and with this size is usually associated the habit of 

 blowing it out with air, and assuming the characteristically upright 

 position. 



That variations have taken place, too, in the most delicate 

 structure of the brain, is shown by certain new instincts, such as the 

 trumpeting of the trumpeters, the cooing of others, and the silence 

 of yet other breeds, as well as by the curious habit of the tumblers of 

 ascending quickly and vertically to a considerable height, and then 

 turning over once, or even several times, in the course of their descent. 

 In contrast to this, other breeds like the fantails have altogether 

 given up the habit of flying high, and usually remain close to the 

 dove-cot. 



Lastly, let me mention that the unusual development of individual 

 feathers, or of groups of feathers, has become a race-character, upon 

 which depend such remarkable structures as the feather-mantle 

 turned over the head in the Jacobins (No. 9), the cap or plume on 

 the head of various breeds, the white beard in the bearded tumbler, 

 the collars which lie like a shirt-collar on the breast, or run down the 

 sides of the neck (Nos. 8 and 10), and the circle of feathers which 

 marks the root of the bill in the Bucharest trumpeter (No. 3). 



After what has been said, it is hardly necessary to add that the 

 size of the whole body differs in different races. But the differences 



