i893- NE ARCTIC REGION AND ITS MAMMALS. 291 



region ' extending southward to about the mean latitude of the Great 

 Lakes, with outlying portions extending further southwards along the 

 principal mountain-system of the continent, and (2) a ' Warm- 

 Temperate Sub-region ' occupying the remaining area." This 

 mode of division (which is shown on Mr. Allen's plate vi.) corresponds 

 pretty nearly with that proposed by Dr. Merriam (see his Bio- 

 geographic Map), who calls those two sub-regions "Boreal" and 

 " Sonoran " ; but upon comparing'the maps of the two authors together, 

 it will be seen at a glance that the minor subdivisions do not 

 exactly correspond, and indeed such particulars must be always more 

 or less matters of opinion. 



In his carefully drawn up tables of North American Mammals, 

 Mr. Allen shows that fourteen genera occur in his Cold-Temperate 

 Sub-region, which do not range to any extent into the Warm- 

 Temperate Sub-region. On the other hand, 33 genera found in the 

 Warm-Temperate do not occur in the Cold-Temperate, while 27 genera 

 are, to a greater or less extent, common to both their sub-regions. 

 He points out that the 42 genera of the Cold-Temperate Sub-region 

 are " either obviously of boreal origin, or find their nearest relationship 

 with boreal types," while of the 62 genera which occur in the Warm- 

 Temperate Sub-region, " about fourteen are wide-ranging southern 

 or subcosmopolitan types, 24 may be regarded as indigenous, and 

 about thirteen are of southern origin." 



Neglecting, therefore, as we have already proposed to do, Mr. 

 Allen's strip of the " Arctic Realm " in the North American Fauna as 

 merely borderland, and, in a similar way, treating the area south of 

 the Mexican Tableland and the extreme southern parts of the 

 peninsulas of Lower California and Florida as merely debatable land 

 between the Nearctic and Neotropical Regions, we find Mr. Allen's 

 " North American Region of the North Temperate Realm " practically 

 identical with the Nearctic Region of Sclater and Wallace. Following 

 the guidance of Mr. Allen and Dr. Merriam, we recognise two 

 sub-regions only in the region, namely, a Northern and a Southern one. 



The Northern Sub-region is composed of Mr. Allen's " Cold- 

 Temperate Sub-region," and the adjacent district on the north which 

 he assigns to the " Arctic Realm." Here the general facies of the 

 Mammal-fauna is much more decidedly similar to that of the Palae- 

 arctic Region than in the Southern Sub-region. Such genera as 

 Ceyvus, Alces, Rangifer, Ovis, Castor, Lagomys, Gulo, and Putorius, betray 

 at once a very strong Palaearctic element. At the same time, a 

 decidedly endemic element is shown by such types as Haploceros, 

 Fiber, Condylnra, Procyon, Mephitis, and Taxidea, which are absolutely 

 unknown in the Palaearctic Mammal-fauna. For this Northern Sub- 

 region of the Nearctic Region perhaps " Canadian " would be the 

 best term, as it embraces the whole of the Dominion of Canada, and 

 the area of the sub-region is therefore at once recognisable by the 

 name. Mr. Allen's term " Boreal " is much too vague. 



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