Mr. Wallace on the Geographical Distribution of Birds . 449 
XLVI.— Letter from Mr. Wallace concerning the Geographical 
Distribution of Birds. 
Batchian, March 1859. 
My pear 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, you 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 Palsearctic Region.. 12,500,000 
—instead of 14,000,000 given by you. 
2. iETHioPiAN Region. In this you make a very large area, 
* See Journ. Proc. Linn. Soc. ii. p. 130. 
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VOL. I. 
