HISTORY OF THE PERISSODACTYLA 319 



ancient known ftitanotheres, which were small and light, had 

 already suffered the loss of the first digit in the fore foot and of 

 the first and fifth digits in the hind foot, but there reduction 

 ceased. With the growing body-weight, long, narrow and slen- 

 der feet would have been a detriment, whereas in swift-running 

 animals, like horses and deer, long and very slender feet are a 

 great advantage. The contrast is both striking and instructive, 

 showing the importance of a short, broad, polydactyl and pillar- 

 like foot to very large and heavy mammals, all of which have 

 feet of this character. 



(10) The hoofs, as shown by the terminal bones (ungual 

 phalanges) which formed their bony cores, were reduced in 

 size until they became mere nail-like excrescences around the 

 border of the massive foot. 



3, 4. Tapiridce and fLophiodontidce. Tapirs and ^Lophiodonts 



The history of the tapir family is not at all satisfactorily 

 known, partly because tapirs are comparatively rare as fossils 

 in all of the Tertiary formations, and still more for the reason 

 that the specimens so far collected are so fragmentary, not a 

 single half-complete skeleton among them. Had these animals 

 actually been as rare in North America as the fossils would seem 

 to indicate, they could not possibly have maintained them- 

 selves for so long a time, throughout nearly the whole of the 

 Tertiary and Quaternary periods. For some reason, probably 

 because they have always been forest-haunting animals, their 

 habits must have kept them in places remote from the areas 

 where the accumulation of sediments was in progress, and thus 

 only occasional stragglers were buried and preserved. 



The rarity and incompleteness of the material render it 

 impossible to give any such full account of the tapirs as is 

 practicable for the horses and ftitanotheres, but the cir- 

 cumstance is less unfortunate in the case of the tapirs than in 

 that of many other families. This is because these creatures 



