16 
ISLAND LIFE. 
[part I. 
the Himalayas there are numbers of birds which have very 
restricted ranges, but those of the Neilgherries are perhaps 
better known, several species of laughing thrushes and some 
other birds being found only on the summits of these mountains. 
The most wonderfully restricted ranges are, however, to be 
found among the humming-birds of tropical America. The 
great volcanic peaks of Chimborazo and Pichincha have each a 
peculiar species of humming-bird confined to a belt just below 
the limits of perpetual snow, while the extinct volcano of 
Chiriqui in Yeragua has a species confined to its wooded crater. 
One of the most strange and beautiful of the humming-birds 
( Loddigesia mirdbilis) was obtained once only, more than forty 
years ago, near Chachapoyas in the Andes of northern Peru ; 
and though Mr. Gould has sent many drawings of the bird to 
people visiting the district and has for many years offered a 
high reward for a specimen, no other has ever been seen ! 1 
The above details will sufficiently explain what is meant by 
the “ specific area ” or range of a species. The very wide and 
very narrow ranges are exceptional, the great majority of 
species both of mammals and birds ranging over moderately 
wide areas, which present no striking contrasts in climate and 
physical conditions. Thus a large proportion of European birds 
range over the whole continent in an east and west direction, 
but considerable numbers are restricted either to the northern 
or the southern half. In Africa some species range over all the 
continent south of the desert, while large numbers are restricted 
to the equatorial forests, or to the upland plains. In North 
America, if we exclude the tropical and the arctic portions, a 
considerable number of species range over all the temperate 
parts of the continent, while still more are restricted to the 
east, the centre, or the west, respectively. 
Generic Areas . — Having thus obtained a tolerably clear idea 
of the main facts as to the distribution of isolated species, let 
us now consider those collections of closely-allied species termed 
genera. What a genus is will be sufficiently understood by a 
few illustrations. All the different kinds of dogs, jackals, and 
1 Since these lines were written, the report conies that fresh specimens 
have been found in the same locality. 
