One of the most remarkable quadrupeds of the high northern regions is the musk-ox (_Ovibos moschatus_), which by some naturalists has been considered as intermediate between the sheep and the ox. It is about the height of a deer, but of much stouter proportions. The horns are very broad at the base, almost meeting on the forehead, and curving downward between the eye and ears until about the level of the mouth, when they turn upward. Its long thick brown or black hair hanging down below the middle of the leg, and covering on all parts of the animal a fine kind of soft ash-colored wool, which is of the finest description, and capable of forming the most beautiful fabrics manufactured, enables it to remain even during the winter beyond 70° of northern latitude. In spring it wanders over the ice as far as Melville Island, or even Smith’s Sound, where a number of its bones were found by Dr. Kane. In September it withdraws more to the south, and spends the coldest months on the verge of the forest region. Like the reindeer, it subsists chiefly on lichens and grasses. It runs nimbly, and climbs hills and rocks with great ease. Its fossil remains, or those of a very analogous species, have been discovered in Siberia: at present it is exclusively confined to the New World. In the Rocky Mountains, from the Mexican Cordillera plateaux as far as 68° N. lat., dwells the wild sheep (_Ovis montana_), distinguished by the almost circular bend of its large, triangular, transversely striped horns, from its relative the Siberian argali (_Ovis argali_), which is supposed to be the parent of our domestic sheep, and far surpasses it in size and delicacy of flesh. Both the American and the Asiatic wild sheep are in the highest degree active and vigorous, ascending abrupt precipices with great agility, and, like the wild goat, going over the narrowest and most dangerous passes with perfect safety. Among the carnivorous quadrupeds of the northern regions, many, like the lynx, the wolf, the bear, the glutton, and other members of the weasel tribe, have their head-quarters in the forests, and only occasionally roam over the tundras; but the Arctic fox (_Canis lagopus_) almost exclusively inhabits the treeless wastes that fringe the Polar Ocean, and is found on almost all the islands that lie buried in its bosom. This pretty little creature, which in winter grows perfectly white, knows how to protect itself against the most intense cold, either by seeking a refuge in the clefts of rocks, or by burrowing to a considerable depth in a sandy soil. It principally preys upon lemmings, stoats, polar hares, as well as upon all kinds of water-fowl and their eggs; but when pinched by hunger, it does not disdain the carcasses of fish, or the molluscs and crustaceans it may chance to pick up on the shore. Its enemies are the glutton, the snowy owl, and man, who, from the Equator to the poles, leaves no creature unmolested that can in any way satisfy his wants.