eys of streams and rivers,
is totally different. The moist soil gives free development to
thickets of various willows, bordered with dense walls of worm-wood
and needle-bearing _Composita_, and interspersed with rich but
not extensive prairies harbouring a great variety of herbaceous
plants; while in the deltas of the Black Sea rivers impenetrable
masses of rush shelter a forest fauna. But cultivation rapidly
changes the physiognomy of the Steppe. The prairies are superseded
by wheat-fields, and flocks of sheep destroy the true steppe-grass
(_Stipa-pennata_), which retires farther east.

The _Circum-Mediterranean Region_ is represented by a narrow strip
of land on the south coast of the Crimea, where a climate similar
to that of the Mediterranean coast has permitted the development
of a flora closely resembling that of the valley of the Arno.

[Illustration: REVEL]

The fauna of European Russia does not very materially differ from
that of western Europe. In the forests not many animals which have
disappeared from western Europe have held their ground; while in
the Urals only a few--now Siberian, but formerly also European--are
met with. On the whole, Russia belongs to the same zoo-geographical
region as central Europe and northern Asia, the same fauna extending
in Siberia as far as the Yenisei and Lena. In south-eastern Russia,
however, towards the Caspian, we find a notable admixture of Asiatic
species, the deserts of that part of Russia belonging in reality
rather to the Aral-Caspian depression than to Europe.

For the zoo-geographer only three separate sub-regions appear on the
East-European plains--the _tundras_, including the Arctic islands,
the forest region, especially the coniferous part of it, and the
Ante-Steppe and Steppes of the black-earth region. The Ural mountains
might be distinguished as a fourth sub-region, while the south-coast
of the Crimea and Caucasus, as well as the Caspian deserts, have
their own individuality.

As for the adjoining seas, the fauna of the Arctic Ocean off the
Norwegian coast corresponds, in its western parts at least, to that
of the North Atlantic Gulf Stream. The White Sea and the Arctic
Ocean to the east of Svyatoi Nos belong to a separate zoological
region connected with, and hardly separable from, that part of
the Arctic Ocean which extends along the Siberian coast as far as
to about the Lena. The Black Sea, of which the fauna was formerly
little known but now appears