"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. We call them fore legs and hind legs. People have two pairs also. We call them arms and legs. So you see our arms correspond to the fore legs of beasts, though we never use them for moving about, except when we go on our hands and knees, or climb trees, or swim in the water. And as for birds--why, their fore limbs are turned into wings, to fly with, so that they walk or hop on their hind limbs only, just as we do. Animals that go on all fours are called _quadrupeds_. Animals that go on their two hind limbs only, like Bird People and House People, are called _bipeds_. A Sparrow's wings are just as much like a mouse's fore legs, as a Sparrow's feathers are like a mouse's fur." "How funny!" said Dodo. "But how are a bird's wings like fore legs, when they haven't got any paws or toes--or fingers--or claws--only just long feathers?" "They have fingers, and some birds' wings have claws; only you cannot see them, because they are all wrapped up in the skin and covered over with the feathers. Some day--not to-day, because you have had a long lesson already--I will show you a bird's wing with only its bones. Then you will see that it has finger-bones at the end, then hand-bones next, then bones that run from the wrist to the elbow, and then one bone that runs from the elbow to the shoulder--almost the same bones that people have in their fingers, hands, wrists, and arms. So you see wings are the same to a bird that fore legs are to a mouse or arms are to us. "I could go through all the inside parts of birds, and show you something like the same parts in people,--stomach and bowels, to take care of the food they eat and turn it into blood to nourish them; lungs to breathe with, and keep the blood pure; heart to beat and thus pump the warm blood into all parts of the body; brain and nerves, which are what birds think and feel with, just as we do with ours; and all their bones, which together make what we call the _skeleton_, or framework of the body, to keep the flesh in shape and support the other organs." "Dear me!" sighed Dodo; "there must be ever so many more things inside of birds that we can't see, than there are outside." "Of course there are!" said the Doctor. "It won't be very hard for you to remember the outside parts, and learn the names of them all. I have told you most of them that you need to remember, to understand the stories I am going to tell you about birds. See here! What do you think of this?" [Illustration: Outside parts of a bird.]