116 THE THEORY OF EVOLUTION 



tually take place. The toes proper are free, giving 

 the "cloven hoof," but the hoofs are very small and 

 the weight is carried upon a soft thick pad. 



Were there time enough to do so, we might trace 

 the development of this family backward, step by 

 step, through all the many stages between the Pleis- 

 tocene and the upper Eocene in quite as unbroken 

 sequence and in as full detail as can be done for the 

 horses. We must, however, pass over all the inter- 

 mediate steps and consider the ancestral camels of 

 the upper Eocene. These were very little animals, 

 hardly larger than a jack rabbit, which had the full 

 complement of teeth, 44 in total number and all with 

 very low crowns. The limbs and especially the feet, 

 are relatively short, the ulna is complete and sepa- 

 rate, as is also the fibula; there are four toes in each 

 foot, though the lateral pair of the hind foot are ex- 

 tremely slender, and there is no co-ossification to 

 form cannon-bones. The hoofs are well developed, 

 in form like those of an antelope, so that there 

 can have been no pad. For the present, the line 

 cannot be carried back of the upper Eocene, the 

 probable ancestors from the middle and lower Eocene 

 being, as yet, represented only by fragmentary 

 specimens. 



In addition to this main stem of cameline descent, 

 which resulted in the modern species, there were 

 two short-lived side branches which should be men- 

 tioned. One, ending in the lower Miocene, was the 

 series descriptively called "gazelle-camels," small 



