While the professor, Washington, Tom and Bill remained behind to make some adjustments to the machinery, and to get things in shape for the night, which, they calculated would soon be upon them, Jack, Mark and Andy went down to the shore of the lake.  The boys cut some poles from the trees, and baiting the hooks with some fat worms found under the bark, threw in.

“Let’s see who’ll get the first bite,” spoke Jack.  “I’m pretty generally lucky at fishing.”

“Well, while you’re waiting to decide that there contest, I think I’ll take a stroll along shore and see if I can see anything to shoot,” Andy remarked.

For several minutes the boys sat in silence on the bank of the lake, watching the play of the vari-colored lights on the water.  Suddenly Jack felt a quiver on his line, and his pole began to shake.

“I’ve got something!” he cried.  Then his pole bent almost double and he began to pull for all he was worth.  “It’s a whopper!” he cried.  “Come and help me, Mark!”

Mark ran to his friend’s aid.  Whatever was on the other end of the line was strong enough to tax the muscles of both boys.  They could hear the pole beginning to break.  But for the excellent quality of Andy’s line that would have parted some time before.

All at once there came a sudden slacking of the pull from whatever was in the water.  And so quickly did it cease that both boys went over backward in a heap.

“He’s got away!” cried Jack, getting up and brushing some of the dirt from his clothes.

“There’s something that didn’t get away!” cried Mark, who had risen to his knees, and was pointing at the lake.  Jack looked and what he saw made him almost believe he was dreaming.

For, emerging from the water, dragging the pole and line the boys had dropped along with it, was a most curious creature.  It was a big fish, but a fish with four short legs on which it was walking, or rather waddling along as much as a duck, with a double supply of feet, might do.

“Say, do I see that or is there something the matter with my eyes?” sung out Jack, making ready to run away.

“It’s there all right!” exclaimed Mark.  “Hi!  Andy!  Here’s something to shoot!” he yelled, for indeed the creature was big enough to warrant attack with a gun.  It was about five feet long and two feet through.

On and on it came, straight at the boys, as if to have revenge for the pain the fish hook must have caused it, for the barb could be seen dangling from its lip.  On and on it came, waddling forward, the water dripping from it at every step.  It had the body and general shape of a fish, save that the tail was rather large in proportion.  As it came nearer the boys noted that the feet were webbed, like those of a water fowl.

“Come on!” cried Jack.  “It may attack us!”

At that moment the creature opened its mouth, showing a triple row of formidable teeth, and gave utterance to a sort of groan and grunt combined.