_Palæarctic Region._—The Palæarctic region is of enormous extent, and includes countries varying greatly in their flora, climate, and elevation. Thus it embraces the Arctic plains of Siberia, the warm regions of Italy, Southern France, and Northern Africa, the forest-clad slopes of the outer Himalaya, and the lofty arid plains of Turkestan and Tibet, scorched by a burning sun in summer and chilled by a still more terrible cold in winter. Its extreme limits in the west are marked by the Canaries and Azores, and in the east by distant Japan; and yet throughout this vast expanse we find a great uniformity of life, as exemplified by the large number of British genera which occur also in Japan. The mammals which are on the whole the most characteristic of this region are the Sheep and Goats, forming a section of the great family of _Bovidæ_; nearly all the species of which are Palæarctic, although we meet with one Goat (_Capra_) in the Nilgherries of Southern India, and a Sheep (_Ovis_) in the Nearctic region. The Musk Ox (_Ovibos_) is characteristic of the Palæarctic and Nearctic regions. At least one species of Camel is characteristic of this region, and it is not improbable that the second may also have originated in it. There are a few characteristic types of Antelopes, such as the Alpine Chamois (_Rupicapra_), the Saiga of Tartary, and the Chiru (_Pantholops_) of Tibet, each of which is represented by only a single species: and we miss the host of Antelopes so characteristic of the Ethiopian region. Deer (_Cervus_) are abundant, although by no means confined to this region; and the Musk Deer (_Moschus_), the sole representative of the subfamily _Moschinæ_, is exclusively Palæarctic. Monkeys, as a rule, are absent, although we meet with one species of _Macacus_ in Northern Africa and at Gibraltar, and some other types on the southern border of Tibet. The Moles (_Talpa_) are mainly Palæarctic, although one species enters Northern India, while the Desmans (_Myogale_) of the Pyrenees and Southern Russia are unknown beyond the limits of this region. The Water-shrew (_Nectogale_) is likewise a peculiar eastern Palæarctic type. Among the Rodents, the Picas or Tailless Hares (_Lagomys_) and the Dormice (_Myoxus_) are essentially Palæarctic forms, only one species of each being found beyond the limits of the region, and the one extra-Palæarctic species of _Lagomys_ occurring in the cognate Nearctic region. The Mice and Rats are represented by the typical genus _Mus_ and other types, and Hares (_Lepus_) and one species of Squirrel (_Sciurus_) are common. The Carnivora include two species of Bears (_Ursus_), Wolves and Foxes (_Canis_), a Lynx and a few species of Cats (_Felis_), as well as numerous weasels (_Mustela_), and some other types.