They were about to follow the current of the river when the head of some strange animal was lifted above the surface of the water near them, followed by a mass of water thrown high in the air by a big tail, which flashed in sight for a moment.  A line of great swirls, like those made by the propeller of a steamboat, led out in the bay and marked the course of the fleeing creature.  Ned and Dick forgot that they were tired, and paddled furiously on the trail until they reached the end of it.  Another line of swirls showed where the creature had gone, and once more they followed him.  Again and again they were led on until they had traveled a couple of miles, when they lost the trail completely.  While they were trying to find it Dick saw the head of the thing lifted for an instant, some two hundred yards away, at the mouth of a little cove.  When they reached the cove they found the water clear and deep, and while drifting quietly on its surface they saw resting on the bottom near them a curious creature about ten feet long, with flippers like a seal and a big, powerful tail set crosswise like that of a dolphin.

“I know what that is,” said Ned excitedly.  “I’ve been reading about the fauna of Florida lately, and this isn’t a fish.  It’s a very rare mammal, a manatee, or sea-cow.  It’s perfectly harmless.  I wonder if we could catch it.  Let’s try it.  I’ll fix a lasso and throw it over the manatee’s head when it comes up to breathe.”

“S’pose you get your rope over its head, what will happen next to the canoe—­and to us?”

“That’s what I want to find out.  Please paddle a little nearer very quietly.  He is beginning to rise,” said Ned, who had made a noose in the end of a harpoon line and was standing in the bow of the canoe, ready to throw it the instant the creature’s nose reached the surface.

“I see our finish,” said Dick as he held his paddle ready to steady the canoe, which was already endangered by Ned’s standing up in it.  The next instant the manatee came to the surface, and as the creature lifted its head Ned threw his lasso over it.  An upward stroke of the big tail of the manatee sent a column of water in the air which half filled the canoe and nearly capsized it, in spite of Dick’s best efforts.  When the commotion subsided Ned had disappeared.  Dick looked wildly over the surface and then into the water, and was just going overboard to search the bottom when Ned’s head appeared on the surface.  At first the boy seemed confused and swam away from the canoe, but turned when Dick called to him.  The canoe was half full of water, and as it would have been difficult for Ned to get aboard without capsizing it, he swam to the nearest key, while Dick paddled the canoe to the shoal water beside it.  As the boys stood in the water bailing out the canoe and examining its cargo, Dick said to Ned: 

“What did your book say about the manatee being a perfectly harmless animal?  I’d sure hate to be spanked by that harmless tail.”