viii PREFACE 



I thus take up Darwin's earlier position, from which he some- 

 what receded in the later editions of his works, on account 

 of criticisms and objections which I have endeavoured to show 

 are unsound. Even in rejecting that phase of sexual selection 

 depending on female choice, I insist on the greater efficacy 

 of natural selection. This is pre-eminently the Darwinian 

 doctrine, and I therefore claim for my book the position of 

 being the advocate of pure Darwinism. 



I wish to exj^ress my obligation to Mr. Francis Darwin for 

 lending me some of his father's unused notes, and to many other 

 friends for facts or information, which have, I believe, been 

 acknowledged either in the text or footnotes. Mr. James Sime 

 has kindly read over the proofs and given me many useful 

 suggestions ; and I have to thank Professor Meldola, Mr. 

 Hemsley, and Mr. E. B. Poulton for valuable notes or 

 corrections in the later chapters in which their special subjects 

 are touched upon. 



GoDALMiNG, 3Iarch 1889. 



