THE FORMATION OF VARIETIES. 179 



pliedly equal, all around; whereas, degeneration is not 

 equally effective, upon all the characters of a species. 

 It reduces some very slightly; much reduces others; 

 and wholly suppresses still others; according to the 

 conditions of life, to which the several races, under na- 

 ture, were subjected. 



The several processes, of formation of varieties under 

 domestication, are nearly all exemplified in the case of 

 the Pigeon. This species, under domestication, is pre- 

 eminently conspicuous among those whose varieties 

 are greatly divergent in character. 



" In practice," says Darwin (p. 1 25 , Origin of Species), 

 " a fancier is, for instance, struck by a Pigeon having a 

 slightly shorter beak; another fancier is struck by a 

 Pigeon having a rather larger beak; and on the ac- 

 knowledged principle that ' fanciers do not and will not 

 admire a medium standard, but like extremes,' they 

 both go on choosing and breeding from birds with 

 longer and longer beaks, or with shorter and shorter 

 beaks." 



"Compare," says he (p. 22, Origin of Species), "the 

 English Carrier, and the shortfaced tumbler, and see 

 the wonderful difference, in their beaks, entailing cor- 

 responding differences in their skulls." 



"The Carrier is also remarkable" (p. 22, Origin of 

 Species), "from the wonderful development about the 

 head" — from "greatly elongated eyelids, very large 

 external orifices to the nostrils, and a wide gape of 

 mouth. The shortfaced tumbler has a beak, in out- 

 line, like that of a finch. * * The Runt is a bird 

 of great size, with long massive beak and large feet ; 

 some of the sub-breeds of Runts have very long 

 necks, others very long wings and tails, others simply 

 short tails. The Barb is allied to the Carrier, but in- 



