1002 © The Perissodactyla. > [Non 
crests of the inferior true molars are generally turned forwards q 
and inwards, showing a tendency to the formation of V's. ` 
um from below; from ; 
Fic. 16. Metamynodon danas S. and Te the same cranium Mus. Compal 
White River bed of DURER From Scott and Citioen:3 in “ Bulletin of 
Zodlogy Cambridge 
The PEE in the structure of the genera of this family 
seen in the loss of incisor teeth, of the fifth digit 
_terior foot, and in the greater co-ossification of various bone 
the skull—among them of the nasal bones,—to eth? je 
offensive dermal horns. In Ccelodonta and Elasmotheriu 
nasal bones are further supported by the ossified nasal pe 
and the last-named genus adds an osseous basis or eve? 
for a horn on the frontal bone. In most of the pace 
cross-crests of the superior molars are compara tively angles 
but in Atelodus and Ccelodonta they display ee valles 
which, on wearing, join each other. In this way 
me surrounded or enclosed. This is especially er 
