chap, ii.] THE ELEMENTARY FACTS OF DISTRIBUTION. 
15 
species or as to its geographical limits being really known. In 
Europe we have a distinct species of ibex (Capra Pyrenaica) 
confined to the Pyrenean mountains, while the true marmot 
is restricted to the Alpine range. More remarkable is the 
Pyrenean water-mole (Mygale Pyrenaica ), a curious small in- 
sectivorous animal found only in a few places in the northern 
valleys of the Pyrenees. In islands there are many cases of 
undoubted restriction of species to a small area, hut these 
involve a different question from the range of species on 
continents where there is no apparent obstacle to their wider 
extension. 
Specific range of Birds. — Among birds we find instances of 
much wider range of species, which is only what might be 
expected considering their powers of flight ; but, what is very 
curious, we also find more striking (though perhaps not more 
frequent) examples of extreme limitation of range among birds 
than among mammals. Of the former phenomenon perhaps 
the most remarkable case is that afforded by the osprey or 
fishing-hawk, which ranges over the greater portion of all the 
continents, as far as Brazil, South Africa, the Malay Islands, and 
Tasmania. The barn-owl ( Strix flammed) has nearly as wide a 
range, but in this case there is more diversity of opinion as to 
the specific difference of many of the forms inhabiting remote 
countries, some of which seem undoubtedly to be distinct. 
Among passerine birds the raven has probably the widest range, 
extending from the arctic regions to Texas and New Mexico in 
America, and to North India and Lake Baikal in Asia ; while 
the little northern willow-wren ( Phylloscopus borealis) ranges 
from Norway across Asia to Alaska, and southward to Ceylon, 
China, Borneo, and Timor. 
Of very restricted continental ranges the best examples in 
Europe are, the little blue magpie ( Cyanopica coold) confined to 
the central portions of the Spanish peninsula ; and the Italian 
sparrow found only in Italy and Corsica. In Asia, Palestine 
affords some examples of birds of very restricted range— a 
beautiful sun-bird (Nectarinea oseci ) a peculiar starling (Amy- 
drus Tristramii) and some others, being almost or quite con- 
fined to the warmer portions of the valley of the J ordan. In 
