138 
In the next Tertiary age, THE HIGHER EOcENE, asecond 
appearance ‘ Orohippus,’ an animal not much larger, and 
whose resemblance to a horse is acknowledged to be 
still distant although neavey than ‘Eohippus;’ in this the 
remnant of the fifth toe has disappeared. 
The third appearance in THE EARLY MIOCENE (less 
recent) is of ‘ Mesohippus,’ of the size of asheep, and with 
but three toes (the changes in dentition in these links are 
parallel with the toes, for the animals benefit.) 
In the fourth form ‘Miohippus” in THE UPPER 
MIocENE, a change is not so apparent. 
A fifth form is found in THE LOWER PLIOCENE (more 
recent) of the size of the Ass; the three toes are still in 
existence, but only one reaches the ground: this Ameri- 
can form is like the European ‘ Hipparion’ which (by 
Atavism) is said occasionally to occur to this day. 
A sixth form occurs in THE UPPER PLIOCENE it is 
true ‘Equus,’ yet not ‘Caballus,’ (our own most beautiful 
servant): it has but one toe, and two rudimentary meta- 
tarsals (splints.) 
These are the Species collected from the Tertiary 
deposits (through that vast Geologic era) which have been 
selected to be ranged in line for the pedigree of the 
American horse long extinct. 
And a similar series, under somewhat similar dates, 
has been supplied for the European horse. 
As the connection between the two hemispheres, where- 
in these changes are said to have been simultaneously 
progressing, is still a bridge in the clouds; it is conceded 
that, although the changes were simultaneous, and parallel 
throughout this tremendous period, yet they took place 
probably “w7thout any intercourse” between these changing 
species: and this I understand to be accounted for by the 
) 
theory of ‘Convergence;’ which if it mean anything must 
