DOMESTIC PIGEOI^^S, 23 



and there is a tendency in the hreed to revert to a character 

 which was lost during some former generation, this 

 tendency, for all that we can see to the contrary, mav be 

 transmitted undiminished for an indefinite number of gen- 

 erations. These two distinct cases of reversion are often 

 confounded together by those who have written on in- 

 heritance. 



Lastly, the hybrids or mongrels from between all the 

 breeds of the pigeon are perfectly fertile, as I can state 

 from my own observations, purposely made, on tlie most 

 distinct breeds. Now, hardly any cases have been ascer- 

 tained with certainty of hybrids from two quite distinct 

 species of animals being perfectly fertile. Some authors 

 believe that long-continued domestication eliminates this 

 strong tendency to sterility in species. From the history 

 of the dog, and of some other domestic animals, this con- 

 clusion is probably quite correct, if applied to species 

 closely related to each other. But to extend it so far as to 

 suppose that species, aboriginally as distinct as carriers, 

 tumblers, pouters, and fantails now are, should yield off- 

 spring perfectly fertile inter se, would be rash in the 

 extreme. 



From these several reasons, namely, the improbability 

 of man having formerly made seven or eight supposed 

 species of pigeons to breed freely under domestication — • 

 these supposed species being quite unknown in a wild state, 

 and their not having become anywhere feral — these species 

 presenting certain very abnormal characters, as compared 

 with all other Columbidae, though so like the rock-pigeon 

 in most res|)ects — the occasional reappearance of the blue 

 color and various black marks in all the breeds, both when 

 kept pure and when crossed — and lastly, the mongrel off- 

 spring being perfectly fertile — from these several reasons, 

 taken together, we may safely conclude that all our 

 domestic breeds are descended from the rock-pigeon or 

 Columbfe livia with its geographical sub-species. 



In favor of this view, I may add, firsth\ that the wild 

 C. livia has been found capable of domestication in Europe 

 and in India; and that it agrees in habits and in a great 

 number of points of structure with all the domestic breeds. 

 Secondly, that although an English carrier or a short- 

 .faced tumbler differs immensely in certain characters from 



