MAMMALS. 
17 
mals to-day. I wonder whether we can find in what 
ways they are like each other?” 
“You told us that they are all fed on milk by 
their mothers when they are young,” said William. 
“ That is why they are all put in the same class.” 
3. “I am glad you remember. But we may find 
other likenesses. What covering on the skin have 
the dog, the cow, the monkey, and the horse?” 
“ They all have hair,” was the reply. 
“ And what have you?” 
“ Hair too,” said Arthur. 
4. “Very well,” continued Mr. Johnson; “and 
that is the covering of 
every mammal. It forms 
the soft fur of the cat, 
the thick wool of the 
sheep, and the stiff 
bristles of the pig. It 
grows even on the seals 
and whales ” Seal ~ showing the Feet or Fli PP ers - 
“ Are seals and w r hales mammals?” asked William 
in surprise. “ I thought that all mammals lived on 
land, and walked.” 
5. “Most of them do,” said Mr. Johnson. “But 
the seals and whales are somewhat fish-like in form, 
and are fitted in other ways for a life in water. 
For this purpose their limbs are short and in the 
form of flippers, of which the whale has but one 
pair. 
( M 387 ) 
B 
