Oct.. 1893 NEARCTIC REGION AND ITS MAMMALS. 289 



of the world as being principally tenanted by IMarsupials, and as 

 being the sole home of the existing Monotremes. Again, South and 

 Central America together form a division easily separable from the 

 remaining portion of the world, after Australia has been subtracted. 

 The " Neotropical Region," as it is usually called, has a family of 

 Marsupials peculiar to it ; it has almost no Insectivores, and it is the 

 home of all the three typical families of the great Order Edentata. 

 Thus we have a very obvious threefold division of the earth's surface, 

 taking Mammals as our text, into what may be called Notogo'a, Neogcra, 

 and A rctogo' a. The vice of this division is that it leaves the great 

 bulk of the earth's surface [Arctogea), which remains after taking off the 

 Australian and Neotropical Regions, of rather unmanageable size, 

 consisting as it does of North America and the whole of the Old 

 World except Australia and its islands. This large area, however, 

 readily falls into four sections — North America, Europe and Northern 

 Asia, Africa, and Southern Asia, which are denominated by Sclater 

 and Wallace the " Nearctic," " Palaearctic," " iEthiopian," and 

 " Oriental " regions respectively. No one pretends to say that these 

 four regions are exact equivalents in zoological value to the two regions 

 first spoken of^namely, the "Australian " and "Neotropical" regions. 

 As Mr. Wallace (" Geogr. Distr.," vol. i., p. 66) has well put it : — 



" It is admitted then that these six regions are by no means of 

 precisely equal rank, and that some of them are far more isolated and 

 better characterised than others ; but it is maintained that, looked at 

 from every point of view, they are more equal in rank than any others 

 that can be found ; while as regards geographical equality, com- 

 pactness of area, and facility of definition, they are beyond all 

 comparison better than any others that have yet been proposed for 

 the purpose of facilitating the study of geographical distribution." 



Mr. Allen and Dr. Merriam seem to be of opinion that when we 

 come to scientific questions we are bound to throw away considera- 

 tions of convenience altogether and to stick to matters of fact. This 

 is a beautiful doctrine, but if the matters of fact are in dispute, as is 

 the case in many of the details of geographical distribution, owing to 

 our as yet imperfect knowledge of the subject, it is far better to adopt 

 some easily comprehensible system, of which the leading features are 

 obviously correct, than to use a more elaborate plan, based upon 

 details that are more or less open to question. Contrast, for example, 

 the six divisions of the world already given, their simple names and 

 their easily-defined boundaries, with Mr. Allen's seven "Primary 

 Life-Regions," their complicated titles and their uncertain limits. 

 Where are we to draw the line between the " American Tropical " 

 and the " South American Temperate Realm," or between the 

 " Arctic " and the " North Temperate," both of which embrace 

 portions of the Old and the New Worlds? Than Africa, as regards 

 its Mammals at least, no part of the world, except Australia, has a 

 better set of characteristic types, such as Hippopotamus, Caiiielopardalis, 

 Orycteropus, Hyrax, and many others. Yet Mr. Allen proposes to 



