Headed by Bobby, the shoal of Barnacle babies set off on their travels. They certainly did not look in the least like settling down. They swam and dived and frolicked and tumbled and whisked about in the dancing waves as if possessed by the very spirit of movement. To such atoms of energy, sitting still on a rock was plainly an impossibility. They were queer, tiny, soft-bodied creatures. Thin, delicate shields on their backs were their only shells. They each had three pairs of legs, one eye, and a funny, spiky tail. As they went they ate hungrily, swallowing sea animals so tiny that scores of them would go into a small girl's thimble. "Look out!" Bobby shouted suddenly. As he spoke he turned to the right and swam for dear life, hiding at last under a tangle of ferny seaweed. The others were too late to save themselves. A great fish had swallowed them all in three snaps of its cruel jaws, and Bobby was left alone in the wide sea. He was badly frightened, but presently he swam out from his hiding-place and continued his travels. It was somewhat lonely, but he soon grew accustomed to that. Indeed, he began to like it. He swam and ate and whisked about in the water as cheerfully as ever, keeping his one eye well opened for possible enemies. A shoal of cousins from a sea rock met him. "Come and play with us," they said. "No," said Bobby; "I'm going to travel." Out to sea he went, amongst all the wonders of the white-crested water. Below him lay great colonies of bright corals and sponges and sea-anemones, living their simple quiet lives. Around him rushed and darted eager, busy fishes, keeping him ever on the move to evade their hungry jaws. Many a narrow escape he had, but he was so nimble that he never was caught. As he grew, his skin and shield became too small for him. "This is most uncomfortable," he thought. Split! Skin and shield dropped off. New ones had been growing underneath, but these at first were soft, and he had to shelter under seaweed till they hardened. To his great comfort they were soon firmer than the old ones. Several times he moulted in this way, and each time the new skin and shield came harder and stronger, making him safer from his enemies. One day a strange thing happened. He lost his appetite. "Whatever is the matter with me?" he wondered. He soon discovered. He was changing his shape. Another eye grew, and three more pairs of legs, and a shield on the front as well as the back. "Well, I am a fine, strong fellow now," he thought. "I feel as if I could do wonders." He swam on faster than ever. Indeed, his activity was marvellous. He seemed to shoot through the water. But, strangely enough, he still could not eat, so it is no wonder that at last he grew tired. "I think I must settle down on something," he said. "This life is really most exhausting. And yet I don't want to sit down on a rock and stay in one place all my life. I wish I could find something moving."