overboard. But then Tom's laughter came to an end as he saw the form of a shark moving swiftly toward the spot.
"A shark! a shark!" he screamed. "Sam, get on board, quick! A shark is after you!"
Sam had gone far down beneath the surface and he did not reappear at once. Then he came up spluttering.
"Gosh! I didn't want a bath! Tom, you"
"Hurry and get aboard, Sam! A shark is after you!"
Sam was about ten feet from the raft, and running to the spot nearest to him, Tom held out the end of his paddle.
"A shark?" gasped the youngest Rover.
"Yes! yes! Catch the end of the paddle!"
Sam made a frantic effort to do so. In the meantime the shark came closer and Tom could see his enormous mouth and sharp teeth clearly. His blood turned to ice in his veins.
Sam made a clutch at the paddle, missed it, and disappeared once more from sight. The shark rushed to the spot and turned in dismay, and driven to desperation, Tom hit the monster over the head with the paddle. Then the shark disappeared also.
The next few seconds were full of agony for
