In the rays the breast fins are broad and long. They are the chief means of swimming. The flat fish have these breast fins extended all along the side of the body. By the wave-like motion of these fins and of the body they swim. In some fish these breast fins are turned to feet, for walking at the bottom of the water. There are one or two kinds of fish that can climb trees. These have the under fins turned to sucker-like plates to help them climb. Did you ever hear of the flying fish? That fish has the breast fins long and wide like wings. The fish can rise from five to twenty feet above the water, and these fin wings support it, so that it can fly about two hundred yards. Thus it escapes from its enemies. You will see some fish with fleshy, finger-like organs near the mouth. These are called barbels. Fish with barbels are bottom feeders. With these barbels they hunt for food in the mud. FOOTNOTES: [29] Both _fish_ and _fishes_ are correct plural forms, and both are used to accustom the child to both words. [30] Also of the ray order. LESSON XLII. WHERE THEY LIVE. Where does the fin family live? “In the water,” you say. Yes. There is perhaps no natural body of water in the world without its fish. There are forty families of fresh-water fish. There are fish that live in water that is partly salt and partly fresh, as where the sea-tides run back into rivers. There are fish that live in the salt water of the ocean. [Illustration: IN FRESH WATER.] The ocean fish are divided into three classes. First there are the coast fish, that seldom go far from shore. They need a certain kind of food and a certain warmth of water that they find near land. Then there are surface, or upper-sea fish, that live far from land, but never very deep in the water. And there are the fish of the very deep sea. The surface, or upper-sea fish, are most of them very strong swimmers. The deep-sea fish live far down where there is little air and almost no light. It is only about twenty years since people began to study deep-sea fish, and as yet little is known about them. Many of the shore, or coast fish, that live in sea-water, enter the rivers to lay their eggs. They arrive in the rivers in the spring, and sometimes go up even hundreds of miles from the mouth to find safe places for their young. Thus these fish are born in fresh water, and grow up in salt water. Among fish of this habit, we find the shad and the salmon. So you see a fish may live part of its time in salt water, part of the time in fresh, and part of the time in the brackish water at the river’s mouth. Some fish, that are accustomed to spend all their lives in sea-water, can be made to live in fresh water, if this is changed gradually.