_Nearctic Region._—The two remaining regions we have to consider are comprised in the New World. The first of these is the Nearctic, which, as already mentioned, has a fauna showing such a strongly marked relationship to that of the Palæarctic region, that it has been proposed to unite the two regions. Among types common to these two regions we may mention closely allied species of true Deer (_Cervus_) as exemplified by the Red Deer and the Wapiti; the allied Bisons of the two regions; the Reindeer and Elk common to both; as well as nearly related, and in some cases identical, species of Cats, Lynxes, Bears, Wolves, Foxes, Beavers, Squirrels, Marmots, and Hares. The Glutton or Wolverene, and the Musk Ox is also common to the Arctic portions of the two regions. The Ungulates are very poorly represented, but we have, in addition to the forms already mentioned, one species of the Palæarctic genus _Ovis_, namely the Bighorn, and the Prong-buck (_Antilocapra_), which is quite peculiar. There are, however, no Perissodactyla. The Raccoons and Coatis (_Procyonidæ_) constitute a family represented out of the New World only by the aberrant Cat-Bear (_Ælurus_) of Nipal. The characteristic American feline known as the Puma extends over this region; but there are no Edentates, and the Marsupials are represented only by a single species of Opossum. Rodents are extremely numerous, and comprise several characteristic types, which alone would tell us what part of the globe we were visiting. The most distinctive are the Pouched Rats (_Geomyidæ_), and the Beaver-like rodents known as the _Haplodontidæ_. True Rats and Mice (_Mus_), which are represented throughout the Old World, are totally wanting in the New, where they are replaced by the Vesper-mice, which may be included in the European genus _Cricetus_, although often separated as _Hesperomys_. This feature alone would seem to justify the distinction of the Nearctic from the Palæarctic region. The Musquash (_Fiber_) is a genus of Nearctic rodents unknown in the Old World. Among other characteristic genera we may mention, in the Carnivora, the Skunk (_Mephitis_) and the American Badger (_Taxidea_). Primates are absent from the entire region.