There the Volga, the Ural, the Syr-darya and the Amu-darya discharge their waters without reaching the ocean, but they bring life to the rapidly desiccating Transcaspian steppes, and link together the most remote parts of Russia.
The Forest Region of the Russian botanists includes the greater part of the country, from the Arctic tundras to the steppes, and over this immense expanse it maintains a remarkable uniformity of character.
On the whole, we may say that the arctic and boreal faunas of Europe extend over Siberia, with a few additional species in the Ural and Baraba region - a number of new species also appearing in East Siberia, some spreading along the high plateau and others along the lower plateau from the steppes of the Gobi.
A further gentle rise in the high steppes leads to the mountains of the West Australian coast, and another strip of low-lying coastal land to the sea.
The plains and steppes already described lie either within or close to the tropics.