CHAP. IV. ] ZOOLOGICAL REGIONS. 61 
half of Ceylon. 4 The Lemurian region; consisting of Mada- 
gascar and its adjacent islands. 5, The Austral-Asian region; 
which is the Indian region of Mr. Sclater without the portion 
taken to be added to the Ethiopian region. 6. The Melanesian 
region; which is the Australian region of Mr. Sclater without 
New Zealand and the Pacific Islands, which form 7. the 
Polynesian region. Mr. Blyth thinks this is “a true classifi- 
cation of zoological regions as regards mammalia and birds.” 
In an elaborate paper on the birds of Eastern North America, 
their distribution and migrations (Bulletin of Museum of Com- 
parative Zoology, Cambridge, Massachusetts, Vol. 2), Mr. J. A. 
Allen proposes a division of the earth in accordance with what 
he terms, “‘ the law of circumpolar distribution of life in zones,” 
as follows: 1. Arctic realm. 2. North temperate realm. 3. 
American tropical realm. 4. Indo-African tropical realm. 
5. South American tropical realm. 6. African temperate realm. 
7. Antarctic realm. 8. Australian realm. Some of these are 
subdivided into regions; (2) consisting of the American and 
the Europzo-Asiatic regions; (4) into the African and Indian 
regions ; (8) into the tropical Australian region, and one com- 
prising the southern part of Australia and New Zealand. The 
other realms each form a single region. 
Discussion of proposed Regions.—Before proceeding to define 
the regions adopted in this work, it may be as well to make 
a few remarks on some of the preceding classifications, and 
to give the reasons which seem to render it advisable to adopt 
very few of the suggested improvements on Mr. Sclater’s 
original proposal. Mr. Blyth’s scheme is one of the least 
natural, and also the most inconvenient. There can be little 
use in the knowledge that a group of animals is found in the 
Boreal Region, if their habitat might still be either Patagonia, 
the West Indies, or Japan; and it is difficult to see on what 
principle the Madagascar group of islands is made of equal 
rank with this enormous region, seeing that its forms of life 
have marked African affinities. Neither does it seem advisable 
to adopt the Polynesian Region, or that comprising New Zealand 
alone (as hinted at by Professor Huxley and since adopted by 
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