602 PBOF. E. B. POULTOIf : NATURAL SELECTION 



The comparison of these details is almost a demonstration o£ 

 the operation of natural selection. "We cannot conceive of 

 natural selection acting other than along some such lines as 

 those which have here been shown to exist ; for it is impossible 

 to believe that very different species with very different natures 

 would present anything but very different variations for its 

 action. On the other hand, we cannot conceive of any theory, 

 not dependent upon the principle of selection, which could 

 produce such extraordinary superficial resemblances among 

 numbers of species by methods which are entirely unlike in all ' 

 their details. 



13. The supposed direct JEffect of Local Forces implies the 

 Hereditary Transmission of Acquired Characters. 



Pinally, the hypothesis which is more commonly than any 

 other substituted for natural selection, has the further dis- 

 advantage that it implies the unproved improbable hypothesis of 

 the hereditary transmission of acquired characters. 



A discussion of this latter hypothesis cannot be attempted here. 

 It will be sufficient to observe that after years of search no 

 particle of evidence in its favour, which can stand the test of 

 examination, has been forthcoming. 



14. Geneeal Conclusions : Natural Selection as the Cause of 

 Mimetic Resemblance and Common Warning Colours. 



I think it is not too much to claim that, even if the theories 

 which have been proposed as substitutes for Natural Selection, 

 have not been destroyed in single Sections of this memoir, — and 

 I confidently believe that they have been thus destroyed over and 

 over again, — their most convinced supporter will admit that they 

 must yield to the accumulated pressure of all the arguments 

 here brought forward. 



The resemblances of mimicry and common warning colours 

 have certain salient features in common, certain peculiarities 

 which are apt to manifest themselves repeatedly ; they also bear 

 certain general relationships to other resemblances in organic 

 nature. In this paper I have attempted to set down all the 

 general statements which can be made as to the phenomena 

 under discussion. These general statements represent an 



