he feathers, hard and horny like the beak, and at the end of
this are four toes, three in front and one behind, and they've all sharp
claws on their ends."

"Very well said, my boy! Now I will show you that such feet as the
Sparrow has are as much like Dodo's as a Sparrow's beak is like her
mouth. Begin with the claws--"

[Illustration: FIG. 1. Insect-eating bill of Robin; 2. Seed-crushing
bill of a Sparrow; 3. Snapping bill of Whip-poor-will; 4. Needle bill of
Hummingbird; 5. Chiselling bill of Woodpecker; 6. Climbing bill of
Paroquet; 7. Tearing bill of Falcon; 8. Grooved drinking bill of Dove;
9. Gleaning bill of Ruffed Grouse; 10. Wedge bill of Plover; 11.
Straight probing bill of Snipe.]

[Illustration: FIG 12: Curved probing bill of Curlew; 13. Spearing bill
of Green Heron; 14. Strainer bill of Duck; 15. Hooked bill of Gull; 16.
Ornamental bill of male Puffin in breeding season.]

"I know!" exclaimed Dodo, "toe-nails! Only I think they need cutting!"

"Of course they are toe-nails," said the Doctor. "Don't nails grow on
the ends of toes? All kinds of claws, on the ends of birds' and other
animals' toes, are the same as nails. Some are long, sharp, and curved,
like a cat's or a Sparrow's, and some are flat and blunt, like ours. I
could show you some birds with claws that look just like our
finger-nails. Toes, too, are pretty much the same; only this Sparrow,
like most other birds, has but four, with three of them in a line in
front, and the other one pointing backward. That is what makes its foot
as good as a hand to hold on with when it perches on slender twigs.
Almost all birds have their toes fixed that way. Some, that do not
perch, have no hind toe; and birds that swim have broad webs stretched
between their front toes, like Ducks. All the different kinds of feet
birds have are fitted for the ways they move about on the ground, or
water, or among the branches of trees and bushes, just as all their
shapes of beaks are fitted for the kind of food they eat and the way
they pick it up. Here are two pictures that will show you several
different kinds of feet. Now you must answer the next question, Nat;
what do toes grow on?"

"Feet!" said Nat promptly, then adding: "But this Sparrow hasn't any
feet except its toes; they grow on its legs, because the rest of the
horny part stands up--I've noticed that in Canaries."

"But all this horny part is the foot, not the leg," answered the Doctor,
"though it does stand