Just because it is set on flat, not upright: and learned men will tell you that those two flukes are the "rudiments"--that is, either the beginning, or more likely the last remains--of two hind feet. But that belongs to the second volume of Madam How's Book of Kind; and you have not yet learned any of the first volume, you know, except about a few butterflies. Look here! Here are more whales coming. Don't be frightened. They are only little ones, mackerel-hunting, like the big one. What pretty smooth things, turning head over heels, and saying, "Hush, Hush!" They don't really turn clean over; and that "Hush" is their way of breathing. Are they the young ones of that great monster? No; they are porpoises. That big one is, I believe, a bottle-nose. But if you want to know about the kinds of whales, you must ask Dr. Flower at the Royal College of Surgeons, and not me: and he will tell you wonderful things about them.--How some of them have mouths full of strong teeth, like these porpoises; and others, like the great sperm whale in the South Sea, have huge teeth in their lower jaws, and in the upper only holes into which those teeth fit; others like the bottle-nose, only two teeth or so in the lower jaw; and others, like the narwhal, two straight tusks in the upper jaw, only one of which grows, and is what you call a narwhal's horn. Oh yes. I know of a walking-stick made of one. And strangest of all, how the right-whales have a few little teeth when they are born, which never come through the gums; but, instead, they grow all along their gums, an enormous curtain of clotted hair, which serves as a net to keep in the tiny sea-animals on which they feed, and let the water strain out. You mean whalebone? Is whalebone hair? So it seems. And so is a rhinoceros's horn. A rhinoceros used to be hairy all over in old times: but now he carries all his hair on the end of his nose, except a few bristles on his tail. And the right-whale, not to be done in oddity, carries all his on his gums. But have no whales any hair? No real whales: but the Manati, which is very nearly a whale, has long bristly hair left. Don't you remember M.'s letter about the one he saw at Rio Janeiro? This is all very funny: but what is the use of knowing so much about things' teeth and hair?