Who can tell me the difference between a mouse and a Sparrow ?" "I can!" said Dodo; "it's all difference; a mouse hasn't any feathers, or any wings, and it has four feet, and a long tail and whiskers and teeth--" "That will do, little girl, for differences; do you see anything alike between a Sparrow and a mouse, Rap ?" "I think the fur is something like feathers, Doctor," answered Rap; "and you told us how a beak was like a mouth without any teeth or lips; then a mouse has four feet and legs; but a bird has only two feet, and two wings instead of four legs and feet like a mouse." "That is just what I want you all to think about," said the Doctor.

"Now listen.

If a Sparrow has a pair of feet that correspond to a mouse's hind feet, what do you think a Sparrow's wings correspond to in a mouse ?" "I should think they would be something like a mouse's fore feet," answered Rap, after thinking a moment.
"That is exactly right.

Birds and beasts are alike in many respects.
They have heads, necks, and bodies; they have tails; and they have limbs.

Beasts have two pairs of limbs.