rOU 11 



Chap. VI. THEIR REVERSION IN COLOUR. 203 



To sum up the six foregoing arguments, which are opposed to 

 the belief that the chief domestic races are the descendants of 

 at least eight or nine or perhaps a dozen species; for the 

 crossing of any less number would not yield the characteristic 

 differences between the several races. Firstly, the improba- 

 bility that so many species should still exist somewhere, but be 

 unknown to ornithologists, or that they should have become 

 within the historical period extinct, although man has had so 

 little influence in exterminating the wild 0. livia. Secondly, the 

 improbability of man in former times having thoroughly domes- 

 ticated and rendered fertile under confinement so many species. 

 Thirdly, these supposed species having nowhere become feral. 

 Fourthly, the extraordinary fact that man should, intentionally 

 or by chance, have chosen for domestication several species, 

 extremely abnormal in character ; and furthermore, the points 

 of structure which render these supposed species so abnormal 

 being now highly variable. Fifthly, the fact of all the races, 

 though differing in many important points of structure, pro- 

 ducing perfectly fertile mongrels ; whilst all the hybrids which 

 have been produced between even closely allied species in the 

 pigeon-family are sterile. Sixthly, the remarkable statements 

 just given on the tendency in all the races, both when purely 

 bred and when crossed, to revert in numerous minute details of 

 colouring to the character of the wild rock-pigeon, and to vary 

 in a similar manner. To these arguments may be added the 

 extreme improbability that a number of species formerly existed, 

 which differed greatly from each other in some few points, but 

 which resembled each other as closely as do the domestic races 

 in other points of structure, in voice, and in all their habits of 

 life. When these several facts and arguments are fairly taken 

 into consideration, it would require an overwhelming amount 

 of evidence to make us admit that the chief domestic races are 

 descended from several aboriginal stocks ; and of such evidence 

 there is absolutely none. 



The belief that the chief domestic races are descended from 

 several wild stocks no doubt has arisen from the apparent im- 

 probability of such great modifications of structure having been 

 effected since man first domesticated the rock-pigeon. Nor am 

 I surprised at any degree of hesitation in admitting their common 



