THE AMERICAN BISON 209 



relationships and affinities would not apart from such 

 evidences have been suspected. Thus the capybara-like 

 creature noticed last but one, suggests the existence of a 

 distant affinity between ungulates and rodents (hares, 

 rats, squirrels, &c.), while the Tillodontia, by the structure 

 of their skull, teeth, and limbs, give rise to the notion that 

 they are related both to the rodents and also to flesh- 

 eating beasts, or beasts of prey, carnivores. Finally, the 

 dinotherium has a certain affinity to the clugong and 

 manatee which are marine leg-less creatures, so that 

 if the group of elephants has really any relationship 

 to the ungulates, then these aquatic animals, entirely 

 devoid of hind limbs, must possess such a relationship 

 also. 



The results at which we arrive must remain largely 

 speculative, until we have gained much fuller informa- 

 tion with respect to forms of life which have for ever 

 passed away. All we can say with certainty at present 

 is, that the odd-toed group and the ruminating and 

 non-ruminating even-toed groups are all very distinct, 

 surviving modified forms of a mass of species which at 

 one time constituted a homogenous group, less diversified 

 in structure than their descendants, and which seems to 

 have been related by affinity to the rodents and possibly 

 also to the carnivorous as well as to the dugong and the 

 manatee. That great group gradually divided itself into 

 two sections, the odd-toed and the even-toed. Of the 

 vast mass of odd-toed forms the immense majority have 

 disappeared, leaving three isolated and very divergent 

 survivors the tapir, the rhinoceros, and the horse. Of 

 the mass of even-toed forms, a vastly greater number 

 persist, although death and destruction have caused the 

 formation of a wide interruption between swine-like 

 creatures and ruminants. Of the latter, the richest 



o 



