58 DARWINISM STATED BY DARWIN HIMSELF. 



appearing by monstrosity, in the foot of the horse, struct- 

 ures which normally exist in the foot of the hipparion " — 

 an allied and extinct animal. In various countries horn- 

 like projections have been observed on the frontal bones 

 of the horse : in one case described by Mr. Percival they 

 arose about two inches above the orbital processes, and 

 were "very like those in a calf from five to six months 

 old," being from half to three quarters of an inch in 

 length. 



CAUSES OF MODIFICATIONS IN THE HOESE. 



With respect to the causes of the modifica- 

 tions which horses have undergone, the con- 

 ditions of life seem to produce a considerable direct effect. 

 Mr. D. Forbes, who has had excellent opportunities of 

 comparing the horses of Spain with those of South 

 America, informs me that the horses of Chili, which 

 have lived under nearly the same conditions as their 

 progenitors in Andalusia, remain unaltered, while the 

 Pampas horses and the Puno ponies are considerably 

 modified. There can be no doubt that horses become 

 greatly reduced in size and altered in appearance by liv- 

 ing on mountains and islands ; and this apparently is 

 due to want of nutritious or varied food. Every one 

 knows how small and rugged the ponies are on the 

 northern islands and on the mountains of Europe. Cor- 

 sica and Sardinia have their native ponies ; and there 

 were, or still are, on some islands on the coast of Vir- 

 ginia, ponies like those of the Shetland Islands, which 

 are believed to have originated through exposure to un- 

 favorable conditions. The Puno ponies, which inhabit 

 the lofty regions of the Cordillera, are, as I hear from 

 Mr. D. Forbes, strange little creatures, very unlike their 

 Spanish progenitors. Farther south, in the Falkland 



