182 MIGRATION AND DISTRIBUTION 



to be obtained only by the discovery of mare's nests, as 

 is the fashion nowadays.* 



He had much correspondence, always of a very 

 friendly nature, with Mr. Wallace, and so far as this 

 question is concerned, it ended with the following 

 letter : 



Magdalene College, Cambridge, 



June 17, 1894. 



MY DEAR WALLACE, 



I thank you very much for the paper you have 

 sent me. I saw the title of it advertised and got a copy 

 of Natural Science accordingly reading it with interest 

 but with no little regret, though I have no fault to find 

 with the way in which you defend your position and 

 attack mine. Indeed, I highly appreciate your delicacy 

 and feel sure of your wish to do nothing but bring out 

 the truth. I should much like to reply to you, but I 

 really don't know when I can find time to do so. I am 

 off on Tuesday for a three weeks' holiday beyond the 

 reach, I hope, of posts. I will only remark now that you 

 proceed on the supposition that my " Holarctic " Region 

 =your Palaearctic and Nearctic whereas the southern 

 boundaries of this last are, in my opinion and that of 

 several American zoologists, very uncertain though to 

 me it is clear that the Neotropical Region extends much 

 more to the northward than you would have it run and 

 probably the same is to be said of the Indian Region. 

 Thus a very considerable number of the genera, which 

 you assign to your Nearctic and Palaearctic Regions, 

 belong really to more southern areas, and by their 

 elimination your lists would present a very different 

 aspect. Again, too, you have omitted from your Nearctic 

 list all the Palaearctic genera of birds which inhabit 

 Alaska, and if I am not mistaken there are several 

 Mammals also, making Alaska essentially Palaearctic. 

 There are also not a few other (as it seems to me) 

 inaccuracies, which would make no small change. 



* Letter to Canon H. B. Tristram, February 16, 1889. 



