Mr. Wallace on the Geographical Distribution of Birds. 449 



XLVI. — Letter from Mr. Wallace concerning the Geographical 

 Distribution of Birds. 



Batchian, March 1859. 

 My dear Mr. Sclater, — Your paper on " The Geographical 

 Distribution of Birds ^'* has particularly interested me, and I 

 hope that a few remarks and criticisms thereon may not be un- 

 acceptable to you. With your division of the earth into six 

 grand zoological provinces I perfectly agree, and believe they 

 will be confirmed by every other department of zoology as well 

 as by botany. On the number of species you give to each pro- 

 vince I can say nothing, yon being in so much better a position 

 than myself for arriving at a correct conclusion ; but in the 

 areas of the several provinces I believe you have made some very 

 important errors, which of course affect materially the propor- 

 tionate richness in species of the several provinces. These I will 

 take the liberty of pointing out, as well as of defining, as closely 

 as possible, the limits of each division. 



1. The PALiEARCTic Region I would extend over all Africa 

 north of the great Desert, for I think none of the peculiar forms of 

 Tropical Africa are found there. For its southern limits further 

 eastwards I take the parallel of 30° N. lat. as an average from 

 Suez to the east boundary of Afghanistan, then turning north, to 

 exclude the Punjaub, follow the Himalayas to Birmah, then bend 

 a little south, and then north again to where the 30th parallel 

 crosses the Yung-ling Mountains on the west of China, and follow 

 the same parallel across China to Chusan. This is, I think, as 

 fair a give-and-take as can be chosen with our imperfect know- 

 ledge. Now for the area : — 



Square miles. 



Continental Europe and Asia 14,850,000 (Humboldt.) 



Deduct Continental part of " Regio Indiea " 

 (Arabia=North Africa) 2,630,000 



12,220,000 

 Add for islands 280,000 



Total area of Palfearctic Region 12,500,000 



— instead of 14,000,000 given by you. 



2. ^Ethiopian Region. In this you make a very large area, 



* See Journ. Proc. Linn. Soc. ii. p. 130. 

 VOL. I. 2 1 



