as its owner swiftly pursued a six-foot tarpon, which escaped by leaping in the air within thirty feet of the canoe, toward which it was headed.  Another clash of the shark brought its huge body within its length of the boys, while the great mouth, with its rows of serrated teeth, razor-sharp, opened wide to take in the tarpon, which leaped wildly ten feet in the air, and turning, plunged head-down straight for Ned as he sat in the canoe, paddle in hand.  Dick started up from his seat, while Ned tried to fend off with the paddle, but the hard, pointed head of the big tarpon tore through the bottom of the fragile canoe as if it had been paper.  A minute later the shattered canoe was floating down the river, while everything sinkable had gone to the bottom.

[Illustration:  “PORPOISES ROLLED THEIR BACKS OUT OF THE WATER”]

Tom, who had been asleep in the bottom of the canoe, was swimming for shore, and Ned, who had not for a second lost his presence of mind, was treading water and supporting the unconscious Dick, who had been struck by the tail of the tarpon as the big fish crushed the canoe.  Even as the tarpon struck the canoe Ned was reaching out for Dick, and the boys went down together.

Then to Ned came the struggle for life—­for two lives.  His only thought was of Dick.  Dick mustn’t drown; Dick’s face must be kept out of the water; he must get Dick ashore.  He swam high, wasting his efforts to keep Dick’s head above the surface.  Strength goes fast when one struggles in the water, and Ned was soon gasping for breath.  As he struck out more and more feebly for the bank, while the current swept him down the stream, he sank lower and lower, until only his eyes were above the surface and his lungs seemed bursting for want of air.  A great shark swept past him, and the wave from the big fish rolled over him.  He felt his senses going, his muscles refused to respond to the call of his brain.  His grasp on Dick was loosening, and the thought of this roused him to renew the struggle.  To save Dick he must save himself; he must breathe; he must not exhaust himself, and above all his mind must not wander.  He was so tired; for himself he would have given up the struggle and dropped into rest, but for Dick—­never!  A great calmness came to him.  He rolled over with his head thrown back until all but his face was under water.  This floated clear of the surface as he lay back and drew air into his smothered lungs in great gulps.  He began to kick out with his feet and was soon swimming on his back toward the bank, making fair progress with little effort.  Some of his strength came back, and he found that he was easily dragging Dick along, happily with his face upward.  Hope took the place of despair, and Ned felt that now he could swim for hours.  He saw the overhanging branches of trees above him and knew he was nearing the bank.  Then suddenly he found himself aground on a shoal with water less than knee-deep.  He dragged the unconscious form of his companion into the jungle on the bank, and a great wave of thankfulness rolled over him as he felt the weak beating of Dick’s heart, which was followed by the familiar smile as the boy opened his eyes.