1886, ] The Phylogeny of the Camelide. 623 
In greater detail, the extinct American forms of this line are 
distributed as follows: 
Eocene. Miocene. Pliocene, 
ee AER, rë A 
| Wasatch, | Bridger. White he PET Pai Equus. 
Pantolestes Cope ..... 5 Er 
Ithygrammodon S. O., I 
? Stibarus Cope.. .... ‘ I 
Poébrotherium Leidy. | 2 
| j 
| 
Leidy.... | 6 
. | y 
| 
{ 
NO 
Eschatius | 
Thet “ni number of genera, nine; of species, twenty-six. 
The development of the brain displays the same progress that 
has been shown by Lartet 
and Marsh to have taken 
place in other lines of 
Mammalia. The accom- 
development of the convolu- 
tions of the hemispheres, 
it is in advance of the Foé- 
= brotherium vilsoni in these 
respects (Figs. 13-14). 
The development of the 
camels in North America 
presents a remarkable par- 
allel to that of the horses. 
The ancestors of both lines 
appear together in the Wa- 
“igs 14.— Procamelus genera Sacre of brain standard types in all our 
Skull Perce ted i ; d 
Fig. 12, one- garea o Tertiary formations; an 
Ww. from Re se U S 
ot tat mer r 1877, Vol. 1v, G. M. Wheeler, they must be 
