192 ZOOLOGICAL GEOGRAPHY. [part iii. 
fact, to these, and the numerous lesser mountains and hills 
which everywhere diversify the surface of Europe, that the 
variety and abundance of its animal life is greatly due. They 
afford the perennial supplies to rivers, and furnish in their 
valleys and ever varying slopes, stations suited to every form 
of existence. A considerable area of Central Europe is oc- 
cupied by uplands of moderate elevation, a comparatively 
small portion being flat and marshy plains. 
Most of the northern and much of the central portions of 
Europe are covered with vast forests of coniferous trees ; and 
these, occupying as they do those tracts where the winter is 
most severe, supply food and shelter to many animals who could 
not otherwise maintain their existence. It is probable that 
the original condition of the greater part, if not the whole, of 
temperate Europe, except the flat marshes of the river valleys 
and the sandy downs of the coast, was that of woodland and 
forest, mostly of deciduous trees, but with a plentiful admixture 
of such hardy evergreens as holly, ivy, privet, and yew. A 
sufficient proportion of these primeval woods, and of artificial 
plantations which have replaced them, fortunately remain, to 
preserve for us most of the interesting forms of life, which 
were developed before man had so greatly modified the surface 
of the earth, and so nearly exterminated many of its original 
tenants. Almost exactly in proportion to the amount of 
woodland that still remains in any part of Europe, do we 
find (other things being equal) the abundance and variety 
of wild animals; a pretty clear indication that the original 
condition of the country was essentially that of a forest, a 
condition which only now exists in the thinly inhabited regions 
of the north. 
Although the sub-region we are considering is, for its extent 
and latitude, richly peopled with animal life, the number of 
genera altogether peculiar to it is not great. There are, however, 
several which are very characteristic, and many species, both 
of the smaller mammalia and of birds, are wholly restricted 
to it. 
Mammalia . — The genera wholly confined to this sub-region are 
