GENERAL CONCLUSIONS. 



1. Natural Selection is primarily a theory 

 OF the cumulative development of adapta- 

 tions wherever these occur ; AND THEREFORE 



IS ONLY incidentally, OR LIKEWISE, A THEORY 



of the origin of species in cases where allied 

 species differ from one another in respect of 

 peculiar characters, which are also adaptive 

 characters. 



2. Hence, it does not follow from the 

 theory of natural selection that all 

 species — much less all specific characters — 

 must necessarily have owed their origin to 

 natural selection ; since it cannot be proved 

 deductively from the theory that no " means 

 of modification " other than natural selec- 

 tion is competent to produce such slight 

 degrees of modification as go to consti- 

 tute diagnostic distinctions between closely 

 allied species ; while, on the other hand, 

 there is an overwhelming mass of evidence 

 to prove the origin of " a large proportional 

 number of specific characters " by causes of 

 modification other than natural selection. 



