THE ANCESTRY OF THE HORSE 167 
are quite small, foreshadowing the time when 
they shall have disappeared entirely. It may 
also'be noted here that the splint bones of the 
horses of the bronze age are a little longer than 
those of existing horses, and that they are 
never united with the large central toe, while 
nowadays there is something of a tendency for 
the three bones to fuse into one, although part 
of this tendency the writer believes to be due 
to inflammation set up by the strain of the 
pulling and hauling the animal is now called 
upon to do. Some of these three-toed Hippo- 
theres are not in the direct line ot ancestry of 
the horse, but are side branches on the family 
tree, having become so highly specialized in 
certain directions that no further progress 
horseward was possible. 
Backward still, and the bones we find in the 
Miocene strata of the West, belonging to those 
ancestors of the horse to which the name of 
Mesohippus has been given because they are 
midway in time and structure between the 
horse of the past and present, tell us that 
then all horses were small and that all had 
three toes on a foot, while the fore feet bore 
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