INTRODUCTION. 5 



tion of every inhabitant of this world. Still less do we 

 know of the mutual relations of the innumerable inhab- 

 itants of the world during the' many past geological epochs 

 in its history. Although much remains obscure, and will 

 long remain obscure, I can entertain no doubt, after the 

 most deliberate study and dispassionate judgment of which 

 I am capable, that the view which most naturalists until 

 recently entertained, and which I formerly entertained — 

 namely, that each species has been independently created 

 — is erroneous. I am fully convinced that species are not 

 immutable; but that those belonging to what are called the 

 same genera are lineal descendants of some other and 

 generally extinct species, in the same manner as the 

 acknowledged varieties of any one species are the descend- 

 ants of that species. Furthermore, I am convinced that 

 natural selection has been the most important, but not the 

 exclusive, means of modification. 



