The various species of rapacious animals are disappearing, together with the colonies of marmots; the insectivores are also becoming scarce in consequence of the destruction of insects; while vermin, such as the suslik, or pouched marmot (Spermophilus), and the destructive insects which are a scourge to agriculture, become a real plague.
Schistocolor), the beaver, variable hare, wild boar, roebuck, stag, reindeer, elk and Phoca annelata of Lake Baikal - all these are common alike to Europe and to Siberia; while the bear, musk-deer (Moschus moschi- f erus), ermine, sable, pouched marmot or souslik (Spermophilus eversmani), Arvicola obscures and Lagomys hyperboraeus, distributed over Siberia, may be considered as belonging to the arctic fauna.
Admixture of Mongolian species, such as Canis corsac, Felis manul, Spermophilus dauricus, the jerboa (Dipus jaculus), two hamsters (Cricetus songarus and C. furunculus), three new voles (Arvicolae), the Tolai hare, Ogotona hare (Lagomys ogotona), Aegocerus argali, Antilope gutturosa and Equus hemionus (jighitai).
These lead on to the sousliks, Spermophilus (or Citellus), in which the incisors (as in the following genera) differ from those of all the squirrels in not being compressed.
6) remarkably heavy, the molar teeth differing from those of Spermophilus and Arctomys by having three instead of two transverse grooves on their crowns.
Caudatus) live at the foot of the mountains, as well as four species of Spermophilus, three of voles, two of the mouse and three of the hamster.
The species, Spermophilus (or Citillus) citillus, is rather smaller than an ordinary squirrel, with minute ears, and the tail reduced to a stump of less than an inch in length.