Chap, v.] ANALOGOUS VARIATIONS. 195 



several races of the pigeon having inherited from a com- 

 mon parent the same constitution and tendency to vari- 

 ation, when acted on by similar unknown influences. 

 In the vegetable kingdom we have a case of analogous 

 variation, in the enlarged stems, or as commonly called 

 roots, of the Swedish turnip and Euta 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 add- 

 ed, namely, the common turnip. According to the or- 

 dinary 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 ten 

 dency to vary in a like manner, but to three separate 

 yet closely related acts of creation. Many similar 

 cases of analogous variation have been observed by 

 Naudin in the great gourd-family, and by various authors 

 in our cereals. Similar cases occurring with insect? 

 under natural conditions have lately been discussed 

 with much ability by Mr. Walsh, who has grouped them 

 under his law of Equable Variability. 



With pigeons, however, we have another case, name- 

 ly, the occasional appearance in all the breeds, of slaty- 

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

 a bar at the end of the tail, with the outer feathers ex- 

 ternally edged near their basis 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 re- 

 version, and not of a new yet analogous variation ap- 

 pearing in the several breeds. We may, I think, confi- 

 dently come to this conclusion, because, as we have seen, 



