ZOOLOGICAL LAWS 505 



doubt that such variations in color are found from district to district 

 within a comparatively small area. 



In addition to the two species of zebra already mentioned, there is 

 the mountain zebra, formerly extremely common in the mountainous 

 parts of Cape Colony and Natal, though now nearly extinct in that 

 area. Its hind legs, as might naturally have been expected from its 

 habitat, are more developed than those of the other zebras, just as these 

 same limbs are also more developed in the kiang of the Himalayas than 

 in any other ass. 



With these facts before us, there can be no doubt that environment 

 is a most potent factor not only in coloration, but also in osteology. 

 No less certain is it that environment is capable of producing changes 

 in animal types with great rapidity. Thus, although it is an historical 

 fact that there were no horses in Java in 1346, and it is known that the 

 ponies now there are descended from those brought in by the Arabs, 

 yet within five centuries there has arisen a race of ponies (often 

 striped) some of which are not more than two feet high. Darwin 

 himself has given other examples of the rapid change in structure of 

 horses when transferred from one environment to another, as, for in- 

 stance, when Pampas horses are brought up into the Andes. 



Another good example is that of the now familiar Basuto ponies. 

 Up to 1846 the Basutos did not possess a single horse, those of them 

 who went down and worked for the Boers of the Orange River usually 

 taking their pay in cattle. At the date mentioned some of them began 

 to take horses instead. These horses were of the ordinary mixed 

 colonial kinds, and we may be sure that the Boers did not let the 

 Basutos have picked specimens. The Basutos turned these horses out 

 on their mountains, where, living under perfectly natural conditions, 

 their posterity within less than forty years had settled down into a well- 

 defined type of mountain pony. 



Nor is it only in the horse family that we meet with examples of the 

 force of environment. The tiger extends from the Indian Ocean, 

 through China up to Corea, but the tiger of Corea is a very different 

 animal from that of Bengal. Instead of the short hair of the Indian 

 tiger the Corean has clothed himself with a robe of dense long fur to 

 withstand the rigors of the north. It is not unlikely that if we had a 

 sufficient number of skins from known localities we could trace the 

 change in the tiger from latitude to latitude, just as I have shown in 

 the case of the Equidas. 



Now whilst there is certainly a general physical type common to all 

 the peoples round the Mediterranean, it by no means follows that all 

 those peoples are from the same original stock. On the contrary, the 

 analogy from man in other parts of the world, as well as that of the 

 Eqnidse, suggests that the resemblance between the Berbers, who speak 



