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 Veragua has a species confined to its wooded crater. 

 One of the most strange and beautiful of the humming-birds 

 {Lodcligesia mircibilis) 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 



^ Since these lines were written, the report comes that fresh specimens 

 have been found in the same locality. 



