22 WIDE DISTRIBUTION OF BEARS. [CH. I 



(11) C. hylocrius. This species of wild goat is 

 found in the Neilgherries and some other ranges of 

 southern India. 



(12) G. severtzowi. This is another Caucasian 

 ibex which Dr Menzbier has added to the two already 

 referred to. 



Here we have an instance of a genus of tolerably wide 

 distribution, but discontinuous. The discontinuity is 

 entirely due to the mode of life of the genus, which 

 frequents high mountains and cannot tolerate the level 

 plain. The mountains are comparable to oceanic islands 

 which can only be reached from time to time and under 

 favourable circumstances. This naturally results in the 

 isolation of those individuals which have migrated from 

 their original home to a neighbouring mountain range ; 

 and as a consequence of this isolation, which precludes 

 admixture with the parent stock, we have the production 

 of new forms, just as in the case of oceanic islands. With 

 this may be compared the distribution of such a genus as 

 the giraffe, which has, or had until very recently, a range 

 of nearly the same extent as measured by miles. But 

 this range is uninterrupted by many tracts of country 

 that are uninhabitable to the animal ; hence there are at 

 most two forms of giraffe. Even the true bears (genus 

 Ursus) may be contrasted. Dr Greve allows nine species 

 and five varieties, hardly more than there are of goats. 

 But the range is enormously larger — nearly the whole 

 of Asia and Europe and nearly the whole of America — 

 and there is nowhere a gap of any kind. 



