lateral strain, because there is more or less twist naturally involved upon that limb. 

 Here again we have an illustration of the perfect joint mechanism. 



Finally, we again examine the rearing horse as typifing the conquest of 

 the horse by man. The animal is placed with the left foot thrust forward, and 

 you have a comparison between the rigid fore limb of the horse and the movable 

 hand or wrist of man ; the man is being brought forward by the charge of the 

 horse, while the horse is resting on the tip of a single toe. (Fig. i.) 



Origin of the Horse. 



The explorations for the ancestors of the horse have been in England, 

 France and in western North America. When the small ancestors of the horse 

 were first found in England and France, tliey were not recognized as such; 

 they were so entirely different from the modern horse, so small and simple in 

 structure. It remained for an American palaeontologist first to recognize, in 

 the rocks in the neighborhood of Fort Bridger, Wyoming, the very first stages 

 in the development of the horse. The credit for that is due to the late Prof. O. 

 C. Marsh and to his talented assistant, Mr. Oscar Harger of Yale University. 

 They carried this type back to what is known as the Eohippus, being so known 

 because of its being the dawn of the modern type. 



The water and land masses of the earth at that time were quite different 

 from what they are at present. We owe to the aridity of our western country, 

 and the absence of vegetation, the exposure of the ancient rocks in which the 

 horse ancestors are embedded, from British Columbia on the north to Texas 

 on the south. In fact, wherever the beds are upturned, we have a series of 

 exposed rock where it is possible to find the remains of the horse in various 

 stages of evolution, owing to the extensiveness of these exposures and to 

 the absence of vegetation. If our western country were covered richly with 

 verdure, as England and France are, we never should have made the wonderful 

 progress that we have in our knowledge of the ancestry of this animal. 

 The special Eocene localities are chiefly in southwestern Wyoming, where we 

 find the so-called mountain horse or Orohippus; in northwestern Wyoming, 

 where we have the dawn horse or Bohippus, a little animal about 12 inches in 

 height. These are followed by the more modern types of horse which approach, 

 or are more obviously related to, the existing animal; they are found east of 

 the Rocky Mountains in the region of the Great Plains, from the Swift Current 

 River of British Columbia on the north to Texas and Mexico on the south. 

 These are the principal areas in which fossil horses for the past thirty or forty 

 years have been discovered, and on which we have directed our attack for the 

 finding of more perfect types. Fig. 10. 



In the lower photograph we have the so-called Eohippus, the dawn horse 

 which was found in the Wasatch exposures of the Big Horn Basin of northern 

 Wyoming, not far south of the famous Jackson's Hole shooting country. This 

 little animal is actually 16 inches or four hands high at the shoulder. A more 

 perfect idea of the size, and one which we can carry away with us, is by compar- 

 ison with the skeleton above it, which is that of the whippet, or small coursing 

 hound, the breeding of which has been carried to such perfection in England. 



