356 BIOLOGY AND ITS MAKERS 
tor of the horse made by Charles R. Knight, the animal 
painter, under the direction of Professor Osborn. 
While the limbs were undergoing the changes indicated, 
other parts of the organism were also being transformed 
Fic. 1os5.—Bones of the Foreleg of a Horse. 
and adapted to the changing conditions of its life. The 
evolution of the grinding teeth of the horse is fully exhibited 
in the fossil remains. All the facts bear testimony that 
the horse was not originally created as known to-day, but 
that his ancestors existed in different forms, and in evolution 
have transcended several genera and a considerable num- 
ber of species. The highly specialized limb of the horse 
adapted for speed was the product of a long seriesof changes, 
