1068 . The Perissodactyla. | [Dec. 
a, One or more internal tubercles of superior molars distinct. 
Inner lobes of inferior molars enlarged ; Hippotherium. 
aa. Internal tubercles of molars not distinct. 
Inner lobes of inferior molars enlarged; Protohippus. 
P 
Fic. 33. Paloplotherium minus Cuv., superior molars, naturab size, from below; 
from Gaudry. From the Upper Eocene of Lebruge. 
Five genera of this family are European, and five are Ameri- 
can. The Eocene genera are European only. Paloplotherium 
is found in the Middle- Eocene, and is, as 
might have been anticipated, more nearly 
allied to the Chalicotheriidze than any other 
genus of this family. Chalicotherium ' 
not far removed from it. Anchilophus !5$ 
Upper Eocene, and is allied to the genus 
just named, and also to Pachynoloph’® 
among the Chalicotheriide. These Pi 
genera constitute, by their similarity, ° 
bond of connection between the three 
families, which, in their later and special- 
ized forms, are very different 
other. Palzotherium is chiefl y 
gi the Upper Eocene, and Mesohippus is oY 
ri š 0- 
' Fic. 34. Paleotherium known from the White River oF lig 
medium Cuv., anterior Eocene and Mio- 
š cene, an age between / 
foot, one-third natural . i i mmences in the 
size; from Gaudry. From Cene. Anchitherium ¢o hippus for 
the Upper Eocene of Paris. Middle Miocene, and has Anc > it re- 
a contemporary. 
mained, as late as the Ticholeptus epoch, i 
Hippotherium existed only in the latter pa re of its 
epoch, consistently with the greatly specialized str? te with it, 
limbs and teeth. The nearly allied Protohippus live teeth iS 
and in Europe a species with the same type of ne : 
found in the Pliocene epoch (Forsyth-Major). ae ; 
