The geographical distribution of animals, with a study of the relations ...

218 ZOOLOGICAL GEOGRAPHY. [part m.and asses, gazelles, two species of antelopes, flying squirrels(Pteromys), ground squirrels (Tamias), marmots, of the genusSpermophihis, with camels and dromedaries, probably nativesof the south-western part of this sub-region. The mostabundant and conspicuous of the mammalia are the greatherds of reindeer in the north, the wolves of the steppes, withthe wild horses,goats, sheep, and antelopes of the plateaus andmountains.Among the curiosities of this sub-region we must notice theseal, found in the inland and freshwater lake Baikal, at an elevationof about 2,000 feet above the sea. It is a species of Callocephalus,closely allied to, if not identical with, one inhabitingnorthern seas as well as the Caspian and Lake Aral. Thiswould indicate that almost all northern Asia was depressedbeneath the sea very recently ; and Mr. Belt's view, of the iceduring the glacial epoch having dammed up the rivers and convertedmuch of Siberia into a vast freshwater or brackish lake,perhaps offers the best solution of the difficulty. 1Plate II.— Characteristic Mammalia of Western Tartary.—Several of the most remarkable animals ofinhabit Western Tartary, and arethe Palrearctic regioncommon to the European andSiberian sub-regions. We therefore choose this district for oneof our illustrative plates.The large animals in the centre are theremarkable saiga antelopes (Saiga Tartarica), distinguished fromall others by a large and fleshy proboscis-like nose, which givesthem a singular appearance.They differ so much from all otherantelopes that they have been formed into a distinct family bysome naturalists, but are here referred to the great family Bovidse.They inhabit the open plains from Poland to the Irtish RiverOn the left is the mole-rat, or sand-rat (Spalax murinus). Thisanimal burrows under ground like a mole, feeding on bulbousroots. It inhabits the same country as the saiga, but extendsfarther south in Europe. On the right is a still more curiousanimal, the desman (Myogalc Muscovitica), a long-snoutedwater-mole. This creature is fifteen inches long, including thetail ; it burrows in the banks of streams, feeding on insects,1Quarterly Journal of the Geological Society, 1874, p. 494.