432 



THE AMERICAN NATURALIST [Vol. XL VIII 



extra-limital in parts of an adjoining province locally 

 approximating the prairie environment. 



The habitat-selection of different animal species re- 

 sults, in precisely the same manner, in similarity of geo- 

 graphic range among ecologically similar animals. These 

 correspondences of distribution point to the existence of 

 definite areas characterized by general similarity of the 

 animal assemblages. As the physical factors of the en- 

 vironment are the same ultimately for animals as for 

 plants, and as the vegetational environment for animals 

 has the same range as the physical environment, we 

 might expect animal communities to have the same geo- 

 graphic distribution as plant communities, and we might 

 expect the area of the plant province to be characterized 

 by distinctive kinds of animals as well as by distinctive 

 kinds of plants. The province is thus not simply a vege- 

 tation province, but a biotic province. This is not a 

 new notion. Rut liven (1908: 388-390) has stated a cur- 

 rent viewpoint as follows : 



Those who are acquainted with the literature of the field zoology of 

 North America are familiar with the fact that, since the time of the 

 Pacific Railroad surveys, naturalists have noted that there are in North 

 America well-defined biological regions. These have been pointed out 

 at various times by Allen, Cope, Merriam, and others, and the fauna of 

 each has been more or less investigated. . . . For example, we have forms 

 of birds, reptiles and mammals characteristic of the southeastern de- 

 ciduous forest region, and still others characteristic of the northeastern 

 coniferous forest region, etc. 



Shelford (.4: 60-4) bases his classification of animal 

 regions upon that of plant regions, as worked out by 

 Schimper (1903) and Transeau (1903, 1905). 



How close the correspondence of distribution of par- 

 ticular animals with that of vegetation provinces may ' 

 is well shown in the case of North American rabbi 

 (Nelson, 1909). The distribution maps shown for certa* 

 species and groups of these animals might almost se 

 as maps of the provinces. Many other animals, ver 

 brate and invertebrate, correspond in area with the p 1 ' 

 provinces. Among the insects listed by Hart (1907 : 205 



