The popular phrase, "As happy as a fish in water," is founded on a truth. In fine weather he floats at his ease, enabled as he is to rise or sink at pleasure, to make himself a balloon more or less filled with air, and therefore lighter or heavier. He moves in peace, rocked and caressed by the wave, and, if he so chooses, even sleeps as he floats. He is at once surrounded and isolated by the unctuous substance which renders his skin and his scales slippery and impenetrable by the water. His temperature varies but little and is neither too hot nor too cold. What a difference between a life so convenient, and that which is allotted to us dwellers upon the land; where at every step we meet with asperities and obstacles, which fatigue and exhaust us as we toil up or down our hills and mountains! The atmosphere varies, and often most cruelly, with our various seasons. For days and nights together, the cold rains pour pitilessly down, penetrating us; at times frozen, and piercing us with its sharp crystal points. The felicity and fullness of life of the fish is shown at the Tropics by the splendor of his colors, and at the North by the swiftness of his motion. In Oceania and the Indian Sea they rove and sport in the oddest forms and colors, taking their pleasure among the corals, and living flowers. Our fish, of the temperate and cold seas, are potent rowers; thorough sailors. Their slender and elongated figures give them an arrowy swiftness and grace of movement, which might serve as ensample to our ship builders. Some of them have as many as ten fins which serve them, at will, as sails or oars, and may be kept wide spread or close-reefed. Their tail, that marvellous rudder, is also the principal oar. The best swimmers have it forked, the entire spine ends there and which contracting its muscles gives the fish his swift motion. The Thornback has two immense fins, two great wings to cleave the waves. His long, supple, and slender tail is a weapon with which to lash and divide the waters. So slender and displacing so little water, this fish has no need of the air bladder which supports the thicker fish. Thus each has the peculiar provisions that fit it for its peculiar locality and surroundings. The Sole is oval and flat that it may glide in the sand, the Eel long and slender that it may glide through the mud, and the Lophies, that they may cling to the rocks, have hand like fins that remind one rather of frogs than fish.