ANALOGOUS VARIATIONS, I49 



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 con- 

 sidered 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 

 vegetable kingdom we have a case of analogous variation, 

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

 Swedish turnip and ruta-baga, plants which several bot- 

 anists 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 maybe 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 conse- 

 quent tendency 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 wath insects under nat- 

 ural conditions have lately been discussed with much abil- 

 ity by Mr. Walsh, w^ho has grouped them under his law of 

 equal3le variability. 



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

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

 birds with two black bars on the wings, white loins, a bar 

 at the end of the tail, with the outer feathers externally 

 edsred near their basis with white. As all these marks are 

 characteristic of the parent rock-pigeon, I presume tiiat no 

 one will doubt that this is a case of reversion, and not of a 

 new yet analogous variation appearing in the several 

 breeds. We may, I think, confidently come to this con- 

 clusion, because, as we have seen, these colored marks are 

 eminently liable to appear in tlic crossed oilspring of two 

 distinct and differently colored breeds; and in this case 

 there is nothing in the external conditions of life to cause 



