166 ANIMALS OF THE PAST 
smaller, being about the size and build of a 
pony, but they were very much like a horse in 
structure, save that the teeth were shorter, 
As they lived during Pliocene times, they have — 
been named “ Pliohippus.” 4 
Going back into the past a step farthen | 
though a pretty long step if we reckon by 
years, we come upon a number of animals very 
much like horses, save for certain cranial pe- 
culiarities and the fact that they had three 
toes on each foot, while the horse, as every on : } 
knows, has but one toe. Now, if we glance at _ 
the skeleton of a horse, we will see on either 
side of the canon-bone, in the same situation — 
as the upper part of the little toes of the Hip- 
potherium, as these three-toed horses are called, — 
a long slender bone, termed by veterinarians _ 
the splint bone; and it requires no anatomical ~ 
training to see that the bones in the two ani- 
mals are the same. The horse lacks the lower 
part of his side toes, that is all, just as man 
will very probably some day lack the last bones 
of his little toe. We find an approach to this 
condition in some of the Hippotheres even, 
known as Protohippus, in which the side toes 
