ALLEN ON GEOGRAPHICAL DISTRIBUTION OF MAMMALS. 333 



both continents are similarly colored, the same color, however, extend- 

 ing only to about the forty-ninth degree of north latitude in ISTorth 

 America, while in Africa it descends to north latitude 18°, and in Asia 

 ranges from north latitude 30° to 25° ! His divisions as recognized in 

 4;he text are still more arbitrary and unphilosophic. 



Mr. Wallace, in his discussion of zoological regions, says, — "The dis- 

 tinction betiveen the characteristic forms of life in tropical and cold 

 countries is, on the whole, very strongly marked in the northern hemi- 

 sphere; and to refuse to recognize this in a subdivision of the earth 

 which is established for the very purpose of expressing such contrasts 

 more clearly and concisely than by ordinary geographical terminology, 

 would be both illogical and inconvenient. The one question then re- 

 mains, whether the !N"earctic region should be kept separate or whether 

 it should form part of the Palsearctic or of the Neotropical. Professor 

 Huxley and Mr. Blyth advocate the former course ; Mr. Andrew ^Murray 

 (for mammalia) and Professor !N"ewton (for birds) think the latter would 

 be more natural. No doubt," Mr. Wallace adds, ''much is to be said 

 for both views," but decides in favor of the separation of the two regions 

 in accordance with Dr. Sclater's scheme.* 



While Mr. Blyth includes North America in his "Boreal Eegion" (as 

 " 2. Neo-septentrional Sub-region"), he adds also Central America and 

 the Antilles (as "3. Neo-meridional Sub-region"), and, still more 

 strangely, the Andean Eegion, with Chili, Patagonia, and the Fuegian 

 and Falkland Archipelagos (as "4. Andesian Sub-region ").f 



Professor Huxley, in writing of the primary ontological regions of the 

 globe, thus observes :— " In a well known and very valuable essay on the 

 Geographical Distribution of Birds, Dr. Sclater divides the surface of 

 the globe primarily into an eastern and a western area, which he terms 

 respectively Palwogcea and Neogcca. However, if we take into considera- 

 tion not merely the minor differences on which the species and genera 

 of birds and mammals are often based, but weigh the morphological 

 value of groups, I think it becomes clear that the Nearctic province is 

 really far more closely allied with the Palsearctic than with the Neotrop- 

 ical region, and that the inhabitants of the Indian and Ethiopian 

 regions are much more nearly connected with one another and with 

 those of the Palsearctic region than they are with those of Australia. 

 And if the frontier line is latitudinal rather than longitudinal, and di- 

 vides a north world from a south world, we must speak of Arctogcca 

 and Notogcea rather than of Neogsea and Palseogsea as the primary dis- 

 tributional arese. The secondary divisions, or geographical provinces, 

 proposed by Dr. Sclater, answer, in great measure, to those which are 

 suggested by the distribution of the Alectoromorphce — except that, in 

 common with many other naturalists, I think it would be convenient to 

 recognize a circumpolar province, as distinct from the Nearctic and 



* Geogr. Dist. Aniin., vol. i, pp. 6.5, 66. 

 t Nature, vol. iii, p. 4"27, March 30, 1871. 



