In the morning the tide was rushing up the river, and with it came rolling porpoises and schools of leaping tarpon.

“Couldn’t you catch one of those tarpon?” asked Molly.

Dick said nothing, but Ned shook his head slowly, and Molly understood that he couldn’t so quickly forget that desperate struggle in the water, during which two lives hung by a thread after a tarpon had wrecked their canoe.

As the Irene sailed up the river birds flew from the trees on her approach, alligators slid from their beds on the banks, and otters lifted their round heads above the surface of the stream.  Six miles from its mouth the river spreads out into a bay, and as the boat was entering it Mr. Barstow called out: 

“There is your manatee, sure enough, boys!”

A big, ugly head appeared beside the Irene for an instant, followed by a column of water thrown in the air by the huge porpoise-like tail of the frightened animal.  The anchor was quickly dropped and the little motor-boat, with Dick at the wheel and Mr. Barstow and Molly as passengers, started in pursuit of the sea-cow.  Captain Hull and Ned were in the skiff, which was towed by the motor-boat.  Every few minutes the long eel-grass of the shallow bay choked the propeller of the motor-boat.  Then the motor was stopped, the skiff pulled under the stern of the power-boat, and Ned, with half his head and shoulders under water, tore the grass from the wheel.  For two miles all eyes scanned the surface of the water without sight of the quarry; then came a shout from Molly: 

“There it is!”

“Take the wheel, Molly; it’s your manatee,” replied Dick.

And the girl, without a hat and with her loosened hair streaming down her back, headed the power-boat straight for the creature, which was distant about the eighth of a mile.  Twice the grass choked the wheel and twice with desperate haste it was cleared by Ned.  The boat had gone many yards beyond the place where Molly had seen the animal when there was a great swirl in the water beside the craft, followed by other swirls, which grew less and less as they led in a straight line up a broad tideway that opened into the upper end of the bay.  A moment later another series of swirls was seen and followed, after which, for a time, nothing was seen, although four pairs of eyes were scanning every inch of the stream ahead of the boat.  Then came a cry from the captain, who had been cannily watching the water behind the craft.  The sea-cow had turned around, and, swimming silently beneath the boat, would have escaped but for the glimpse the captain got of him as he rose to breathe just before reaching a bend in the stream, which would have hidden him from his pursuers.  Soon the motor-boat was again on his trail, never to leave it till the creature was a captive.  For the manatee was tired and had to come to the surface for breath at shorter and shorter intervals, until the power-boat almost ran over him at every turn.