Some of them, as they lie in their webs, fold up their legs and look like a dead leaf. One spider puts a row of dead leaves and moss all along her web. She lies on this row, and looks like part of it. Birds cannot see her, as she lies in this way. One small bee that lives in trees is green, like a new leaf. The bees, in brown, black, and gold, look like parts of the flowers on which they alight. Birds and beasts that live in snow lands, are often white, as the polar bear and the eider duck. Snakes that live on trees, or on the ground, are often brown or green. They look like the limbs of trees. Little lizards in walls are gray like stone. In woods, they often are the color of a dead twig. These things can fold up, or stretch out, and look like twigs, or leaves, or balls of grass or hay. All this will keep them from being seen by animals that would kill them. Some of them you know have hard shells to shield them. Did I not once tell you how fast they move? They dart and run and jump, quick as a flash of light. That helps them to get out of the way. Did I not tell you, also, how the crab has his eyes set on pegs? He can turn them every way to see what is near him. The insect and the spider do not have their eyes on long pegs. Some kinds have six or eight eyes. These eyes are set in a bunch, and some face one way, some another. They can see all ways at once. Then, too, so many small live things grow each year, that they cannot all be put out of the way. Each crab will lay more eggs then fifty hens. One spider has more baby spiders than you can count. One bee has more new bees in the hive each year than there are people in a large city. In a wasp’s big nest there are, no doubt, as many wasps as there are leaves on a great tree. Of the creatures which it is most easy to kill, very many are made. And so, while many of them perish each day, many are left to live. LESSON XXXIV. SHELL-FISH. Have you not all heard the song, “Rock-a-by Baby upon the Tree-top”? What babies live in tree-tops? You will say, “Bird, wasp, bee, and spider babies swing in the trees.” Do you not know that there are small cradles that rock all day long on the waves? Up and down, in the sun, on the water, rock the cradles of many shell-fish. What are shell-fish? They are soft animals that live in hard shells. But you must know that these are not true fish. A true fish is an animal that lives in the water, and has a back-bone. The back-bone of a fish is very much like your back-bone. All fish can swim. Most of them have fins and scales. Very many of them have long, slim, smooth bodies, that will glide easily through the water. All of you can see fish, in the ponds, lakes, or brooks near your home. You often have them to eat on your table. If you live in the city, you can go to the place where they sell fish and look at them. In some other book I may tell you a little about the true fishes.