144 ON THE ORIGIN OF SPECIES 



Distinct species present analogous variations; and a 

 variety of one species often assumes some of the characters 

 of an allied species, or reverts to some of the characters of 

 an early progenitor. — These propositions will be most 

 readily understood by looking to our domestic races. 

 The most distinct breeds of pigeons, in countries most 

 widely apart, present sub- varieties with reversed feathers 

 on the head and feathers on the feet, — characters not 

 possessed by the aboriginal rock-pigeon ; these then 

 are analogous variations in two or more distinct races. 

 The frequent presence of fourteen or even sixteen tail- 

 feathers in the pouter, may be considered as a variation 

 representing the normal structure of another race, the 

 fantail. I presume that no one will doubt that all 

 such analogous variations are due to the several races 

 of the pigeon having inherited from a common parent 

 the same constitution and tendency to variation, when 

 acted on by similar unknown influences. In the vege- 

 table kingdom we have a case of analogous variation, 

 in the enlarged stems, or roots as commonly called, of 

 the Swedish turnip and Ruta baga, plants which several 

 botanists rank as varieties produced by cultivation from 

 a common parent : if this be not so, the case will then 

 be one of analogous variation in two so-called distinct 

 species ; and to these a third may be added, namely, 

 the common turnip. According to the ordinary view 

 of each species having been independently created, we 

 should have to attribute this similarity in the enlarged 

 stems of these three plants, not to the vera causa of 

 community of descent, and a consequent tendency to 

 vary in a like manner, but to three separate yet closely 

 related acts of creation. 



With pigeons, however, we have another case, namely, 

 the occasional appearance in all the breeds, of slaty- 

 blue birds with two black bars on the wings, a white 

 rump, a bar at the end of the tail, with the outer 

 feathers externally edged near their bases with white. 

 As all these marks are characteristic of the parent rock- 

 pigeon, I presume that no one will doubt that this 

 is a case of reversion, and not of a new yet analogous 



