II. 



On the Zoo-Geographical Areas of the World, 

 illustrating the Distribution of Birds. 



I HAVE been asked to tabulate the different regions, sub-regions, 

 etc., of the world, of which I spoke, and which I illustrated in 

 my recent course of lectures on the " Geographical Distribution of 

 Birds " at the Royal Institution. I do this with some hesitation, be- 

 cause, as I explained in these lectures, our want of zoological 

 statistics for vast tracts of the Old World makes it almost impossible to 

 give exact definitions of the natural areas of any of the Palaeogcean 

 divisions of the globe. 



With America it is different, as has been shown during the last 

 few j'ears by the admirable work of Dr. C. Hart Merriam and Mr. 

 J. A. Allen on the distribution of North American Mammals, by 

 means of which these authors have presented us with excellent maps 

 defining the natural regions of the North American fauna. Mr. Allen 

 has also recently published ("Auk," 1893, pp. 97-150 pis. iii., iv.) a 

 separate paper on the zoo-geographical divisions of North America 

 based upon the class Aves, and in my lectures I have followed the 

 main conclusions of this paper, as I think it is better for ornitho- 

 logists to adopt faunal regions based upon the distribution of birds 

 alone, when we have some data to go upon. Until Mr. Allen 

 published his avi-geographical maps, I was only too content to work 

 by means of the maps furnished by Dr. Hart Merriam and himself 

 from a study of the mammalia of North America, but I believe that we 

 shall ultimately arrive at sounder conclusions with regard to the 

 zoo-geographical divisions of the earth's surface, if each section of 

 zoologists works out the statistics of his own branch, independently of 

 those of other zoologists, so that at some future date the results can 

 be correlated. This I can hardly expect to see accomplished in my 

 day, but I hope that the present paper may be found to be a small 

 contribution to this desirable result. 



The American naturalists may well be envied for, and congratu- 

 lated by their European colleagues on, the success which has resulted 

 from their patient collection of materials. This has extended over 

 many years, and now leaves them in the proud position of having 

 better statistics to work upon than are possessed by the ornithologists 



