THE FOSSIL HORSE. 309 



It thus seems probable that the musk ox represents 

 one of the most ancient forms of life now existing 

 among the mammalia of the modern world. 



Remarkable also is the fact that the most note- 

 worthy examples of these primeval types of animals 

 seem to be preserved where the greatest extremes 

 of climate exist: viz. in the hottest regions (Central 

 Africa) and in the coldest (the Arctic Zone). If this 

 be so, it is a wonderful example of that strange 

 power sometimes exercised by Nature, of maintaining 

 the existence of particular species under what would 

 seem to be the most unfavourable possible conditions; 

 whilst we have numerous instances of others which 

 have flourished under circumstances where everything 

 seemed to favour them, and yet they have dwindled 

 and become extinct; of this latter, perhaps we might 

 venture to quote the case of the disappearance of the 

 horse (var., .Equus Curvidens [Owen]) from the great 

 plains of South America, as a good illustration : where 

 this ancient horse has left nothing except its fossil 

 bones to testify to the fact of its existence; then 

 about 1537, when the Spaniards came to settle there, 

 they brought with them and landed the Spanish barb 

 on the banks of the Rio La Plata, which has since 

 flourished so enormously that it has overspread the 

 whole area of the region of the pampas with immense 

 bands of tame and also of wild horses. So numerous 

 have the barb horses become, that we have been, 

 in our time, to places where a fairly good horse 

 could be purchased for six dollars and even for less, 

 while thousands of mares as we have elsewhere 

 pointed out were annually slaughtered for the value 

 of their hides and bones. Now the variety of 



