20 
FIRST BOOK. 
Skull of Horse. 
8. Now look at the gap between the front 
and the back teeth. That is where the bit goes. 
Behind it, there is a row of broad, flat teeth for 
chewing and grinding the food. Six grinders 
grow on each side at the top, and the same 
number at the 
bottom. So there 
are twenty teeth in 
each jaw." 
9. Yes/' said 
Tom. " I counted 
them as you were 
speaking. " Here. 
Spot!" he called to his dog, who was scampering 
round. " Come and show your teeth." 
You see that Spot's teeth are not like the 
horse's teeth," said Mr. Hill. ''That is because 
the dog feeds on flesh, and the horse on plant 
food." 
10. ''And the two animals have not the same 
kind of feet," said Tom. 
" No ; the horse has hoofs. These are not split 
like the hoofs of cows, sheep, and goats, but are 
solid and single. Is it not strange that the horse 
has only one toe on each foot? The end of it is 
hidden by the large nail which forms the hoof" 
11. " The hoofs would break and wear away if 
iron shoes were not nailed on to them," said Tom, 
