THE HORSE 233. 
known as the pastern, coronary, and coffin bones, have their 
counterparts in the three joints of the middle finger. The 
last of these, the coffin bone, carries the thickened nail 
or hoof on which the animal walks. That is, the Horse 
walks—so far as his fore-limbs are concerned—on the nails 
of his middle fingers. The two splint bones are the remains 
of the second and fourth metacarpals, or of what in the 
human hand would be the two bones on either side of the 
middle bone of the palm. 
The ancestors of the Horse, that is the animals 
from which the horse was evolved, were small creatures— 
about the size of a well-grown dog —with five digits on each 
limb, which lived in the woods and moist situations. In 
later ages the Horse roamed about on dry firm plains, and 
to suit its changed condition of life, its limbs gradually 
altered, bringing about the disappearance of certain bones 
and the modification of others, until, instead of five toes or 
fingers, it now has only one. It may be mentioned that 
the thumb of the hand is known as the first digit, and the 
little finger as the fifth. 
In a similar way the reader, by examining the hind limb, 
will be able to determine the correspondence between the 
bones forming it and those found in the human leg or in 
the hind limb of the Cat or Rabbit. 
This arrangement of bones by which the heel and wrist 
are raised from the ground gives three segments to the 
limbs instead of two, and, as each segment acts as a lever, 
greatly increases the propelling power of the animal. The 
elasticity of the joints above the hoofs prevents jarring or 
shock when the animal is moving along. 
The edges of the hoof do not quite meet behind, the 
space being filled with a thick mass of tough skin somewhat. 
softer than the hoof proper. This is the “sole” of the 
hoof and corresponds with the pads on the feet of the Dog 
