The boys lost no time in getting down to the beach. They found it hard and firm, and made their way to the strip of grass-covered land lying beyond. Up and down they wandered, finding many curious and beautifully marked shells where the waves had washed them. Suddenly Jack gave a big jump and let out a yell. "What's the matter?" asked Mark. "I thought I saw one of those cocoanuts move," answered Jack, pointing to where several of the big shaggy fruits lay under a tree from which they had fallen. "I guess you're right," spoke Mark. "I certainly saw one of them take a little side step. I wonder what does it." As the boys watched they were surprised, to see one of the cocoanuts come toward them, apparently advancing without any visible means of locomotion. "This is a queer country," remarked Jack, getting ready to run in case the strangely moving cocoanut might be a warning of danger. "Look! There's a whole lot of them moving," cried Mark. Sure enough a dozen or more of the nuts began to advance toward the lads. The boys were not so much afraid as they were surprised. But a few seconds later the reason for the strange sight was made plain. As they looked they saw one of the nuts roll down a little mound of sand. Then they noticed that a big land crab was on the tiny hill and it was evident that the nut had fallen from his claws. "It's the crabs!" exclaimed Mark. "I remember reading about them now. They come ashore from the water where they live part of the time and get the cocoanuts. Then they smash the shells by pounding the nuts on a stone and eat the white meat inside. They are called cocoanut crabs." "I was beginning to think we were in some enchanted land," spoke Jack. "Well, it certainly looked queer," agreed Mark. For some time the boys watched the strange sight. Then they walked along the beach, seeing several large star fish, and some big horse-shoe crabs that had been stranded by the tide. "Look at that immense turtle!" exclaimed Mark, as one of the creatures scuttled over the sand toward the sea. "I'll bet she's been laying eggs!" "Perhaps so." They made a rush for the tortoise but were not quick enough, for she slid into the water and made off. "Here's her nest, anyhow," called Jack, as he pointed to some eggs, thinly covered with sand. "Let's go back and take them with us. I've heard they are good eating." Jack and Mark started to gather up as many of the eggs as they could in their hats. While they were thus engaged they heard a call from the ship and looked up to see coming toward them, all of the ship's company except Washington. "I wonder if anything could have happened," spoke Mark. He and Jack dropped the eggs and started on a run toward the stranded ship. They were reassured, however, when they saw the professor waving his hand at them. When he got within hailing distance the inventor called: