In considering the mammals of this subregion, it should be remembered that they are not uniformly distributed throughout even one subdivision, but in a scattering way and in accordance with their habits and stations, and also in accordance with a gradual change to the south, following the changing temperature. The Muskrat will not be found far from water or the Porcupine from woods. Especially characteristic of the Canadian subregion are the Old World types of deer, none of which range farther south than the Transition zone. The Wapiti, erroneously called the Elk (_Cervus canadensis_), is very closely allied to the European Stag (_C. elaphus_) and still more closely to the Stag of the Thian Shan in Central Asia (_C. eustephanus_). So great is the resemblance, that some naturalists would refer all three forms to a single species. The Moose (_Alce americanus_), which should be called the Elk, is so near to the Scandinavian Elk (_A. machlis_) that it is hardly distinguishable as a separate species, and the Woodland Caribou (_Rangifer caribou_) is the American representative of the Lapland Reindeer (_R. tarandus_). The so-called Rocky Mountain Goat (_Oreamnos montanus_), a peculiar and aberrant form of the Chamois subfamily of the Antelopes, is confined to the subregion. The Mountain Sheep (_Ovis montana_, _O. dalli_) are represented by three or four species, one of which extends into the Sonoran region, as does also the Bison, wrongly called Buffalo (_Bison bison_), which is nearly allied to the European _B. bonasus_. In Cæsar’s time the European Bison (German, Wisent) ranged through Germany and is described in his account of the Hercynian Forest; but the advance of civilization has almost exterminated it, only a few small herds being maintained by the most rigid protection in Russia and in the Carpathian Mountains. Of the Carnivora, the weasels, martens, Fisher, Mink and Ermine are Boreal, as are the Wolverene (_Gulo_) and the Grey Wolf (_Canis_), the three last-named extending also into the Arctic zone. Essentially Boreal, though reaching and entering the Sonoran, are the bears (_Ursus_), the red foxes (_Vulpes_), the otters (_Lutra_) and the Old World shrews (_Sorex_), while the Star-nose Mole (_Condylura_) and the mole-shrews (_Urotrichus_) do not extend south of the Transition zone. Probable intruders from the south into the Boreal subregion are the pumas, or “mountain lions,” which just enter the subregion, the Canada Lynx (_Lynx rufus_) and one species of skunks (_Mephitis_), the Raccoon (_Procyon lotor_), Badger (_Taxidea americana_) and the American deer (_Odocoileus_). A large number of rodents are characteristically Boreal: marmots, or woodchucks (_Marmota_), the Sewellel (_Aplodontia rufa_), lemmings (_Myodes_), Jumping Mouse (_Zapus_), the Canada Porcupine (_Erethizon dorsatus_) and the pikas, “tailless or whistling hares” (_Ochotona_). Boreal rodents that enter the