358 MY LIFE 



extracts. The larger portion is occupied with remarks on the 

 comparative riches of our respective regions in the various 

 families of beetles, founded on a letter I had received from 

 him a few months before, which, though very interesting to 

 entomologists, are not suitable for reproduction here. I then 

 touched on the subject of my paper referred to at the end of 

 the last chapter. 



" To persons who have not thought much on the subject 

 I fear my paper on the ' Succession of Species ' will not 

 appear so clearly as it does to you. That paper is, of course, 

 merely the announcement of the theory, not its development. 

 I have prepared the plan and written portions of a work 

 embracing the whole subject, and have endeavoured to prove 

 in detail what I have as yet only indicated. It was the pro- 

 mulgation of Forbes's theory of ' polarity ' which led me to 

 write and publish, for I was annoyed to see such an ideal 

 absurdity put forth, when such a simple hypothesis will 

 explain all the facts. I have been much gratified by a letter 

 from Darwin, in which he says that he agrees with ' almost 

 every word ' of my paper. He is now preparing his great 

 work on ' Species and Varieties,' for which he has been collect- 

 ing materials twenty years. He may save me the trouble of 

 writing more on my hypothesis, by proving that there is no 

 difference in nature between the origin of species and of 

 varieties ; or he may give me trouble by arriving at another 

 conclusion; but at all events, his facts will be given for me to 

 work upon. Your collections and my own will furnish most 

 valuable material to illustrate and prove the universal applic- 

 ability of the hypothesis. The connection between the suc- 

 cession of affinities and the geographical distribution of a 

 group, worked out species by species, has never yet been 

 shown as we shall be able to show it. 



" In this archipelago there are two distinct faunas rigidly 

 circumscribed, which differ as much as do those of Africa 

 and South America, and more than those of Europe and 

 North America ; yet there is nothing on the map or on the 

 face of the islands to mark their limits. The boundary line 

 passes between islands closer together than others belonging 



