228 ANIMAL ACTIVITIES. 
palms, we could hasten only by rising on fingers and 
toes. Should we so rise it is easy to see that the little 
finger and the thumb would not touch the ground. 
They would hang as useless members behind the 
other fingers. Rising still more, the weight would rest 
wholly on the middle finger, and two more fingers 
would become useless. Something like this has prob- 
ably taken place gradually in the development of digi- 
tigrade feet. 
The Horse’s Foot. The ancestry of the horse has 
been traced back very carefully for thousands of years 
Fic. 191.—Feet of Ancestors of Horse. The figures indicate the num- 
bers of the digits in the five-fingered hand of most mammals. 
before man dwelt upon the earth. It has been found 
that the horse is probably a descendant of a five-toed 
animal not much larger than a sheep. From this 
animal the line of descent has been followed down 
through the ages, the various forms showing the loss 
of toes, one after another, until only one now remains 
for each foot. The splint bones seen on each side of 
the long metacarpal and metatarsal bones of the horse 
are all that remain of the two toes which last dis- 
appeared. 
