THE STORY OF THE HORSE 229 
reaches his modern splendid development. During 
the early Quaternary the horse was perhaps in some 
of his representatives a larger creature than he is to- 
day. Each foot now has but a single toe. The nail 
has spread around firmly and heavily, until it has be- 
come a splendidly developed hoof, permitting the ani- 
mal to travel with speed over firm and often stony 
ground. The side toes have disappeared completely 
from the outside of the horse’s leg, although upon re- 
moving the skin it is easy to find the long splints, 
which are the remnants of toes, which have not yet 
quite disappeared. His heel has been lifted in the air 
until it is eighteen inches off the ground, and he is 
standing like an expert dancer upon the tip of his toe. 
The body of the horse thus being lifted far off the 
ground, a new development becomes necessary. All 
through the growth of the creature the neck and head 
have been obliged to lengthen correspondingly. Every 
animal must be able to bring its head down to the 
level of its feet in order that it may drink. Various 
animals use different methods to accomplish this re- 
sult. The giraffe, with his enormously long legs, has 
a correspondingly long neck, which lowers his mouth 
to the ground. Even with this extended neck the 
giraffe’s legs are so exceedingly long that he is obliged 
to spread his front feet when he wishes to reach the 
ground with his head. The elephant has pursued ex- 
