56 VARIATIONS, DUE TO REVERSION. 



On page 382, Vol. ii, Animals and Plants, &c, he 

 says : 



" Organs which are naturally rudimentary, in The 

 parent species, become partially re-developed in the 

 domesticated descendants. Thus, cows, like most 

 other ruminants, properly have four active, and two 

 rudimentary mamma ; but, in our domesticated ani- 

 mals, the latter occasionally become considerably de- 

 veloped, and yield milk. * * * The hind feet of 

 dogs include rudiments of a fifth toe, and in certain 

 large breeds, these toes, though still rudimentary, be- 

 come considerably developed and are furnished with 

 claws. In the common hen, the spurs and comb are 

 rudimentary, but in certain breeds, these become, inde- 

 pendently of age, or disease of the ovaria, well devel- 

 oped. The stallion has canine teeth, but the mare has 

 only traces of the alveoli, which, as I am informed by 

 the eminent veterinary, Mr. G. T. Brown, frequently 

 contain minute, irregular nodules of bone. These 

 nodules, however, sometimes become developed into 

 imperfect teeth, protruding through the gums, and 

 coated with enamel ; and, occasionally, they grow to a 

 third, or even a fourth, of the length of the canines in 

 the stallion. With Plants, I do not know whether the 

 re-development of rudimentary organs, occurs more 

 frequently under culture, than under nature." 



On page 177, Origin of Species, he says : 



" Rudimentary parts, it has been stated by some 

 authors, and I believe with truth, are apt to be highly 

 variable. * * * Rudimentary parts are left " (i. e. 

 subject) " to the tendency to reversion." 



On page 380, Animals and Plants, &c, he says : 



" With cultivated plants, it is far from rare to find 

 the petals, stamens, and pistils represented by rudi- 

 ments, like those observed in natural species. So it 



