“A little slower, Dick.  It is getting darker in here now and I do not want to run into anything.”

“Slower it is, Jack.  It would not be any fun to stave a hole in the bottom of the boat.  It doesn’t belong to us.”

“That would be reason enough for not daring, with some persons,” said Jack with a low laugh.  “They will take care of their own things, but are careless with those belonging to others.”

“The woods are full of such, Jack.”

Jack rowed with one hand, drawing in his other oar so that it might not strike the rocks in case the passage narrowed, and then got out his pocket flash and shot a strong ray ahead of him.

“Good gracious! what’s that?” suddenly exclaimed Percival in accents of terror.  “Back water, Jack, for heaven’s sake!”

“What is it, Dick?” asked Jack, turning his head and sending the light directly in front of him.  “I don’t see anything.”

“It’s gone, Jack, or the light does not strike it now, but it was something awful.  It fairly gave me the creeps to look at it.”

“But what was it, Dick?” and Jack slowly turned the light this way and that so as to get a sight at the object which had so terrified Percival.

“I don’t know.  It had two awful eyes and a beak and a lot of legs, or arms, or whatever they were, and a fat body which—­there it is, Jack!”

Jack saw it and shuddered.

“It’s a devil fish, an octopus, Dick,” he muttered, turning the light now full upon the grisly object squatting on a rock at the farther end of the water cave and glaring balefully at the boys through his blood-red eyes, like some demon of the deep, the very mention of which might send terror to the bravest hearts.

“We’d better get out quick, Jack!” gasped Percival.  “If that fellow——­”

What he might have said was cut short by a sudden splash in the water which caused the boat to rock violently and dashed the spray in their faces.

Then there was a whip-like sound and Jack felt himself struck by something which quickly wound itself about one arm and a part of his body and swiftly pulled him out of the boat.

He dropped his flashlight, but as he left the boat his free arm swung out and his hand touched something which he seized in an instant.

It was the short hatchet on the thwart and he had seized it by the helve, well up toward the top.

With the swiftness of thought itself he realized what had happened.

The octopus had wound one of its tentacles about his arm and body and, clinging to them with a tenacity which he could not overcome, had pulled him out of the boat.

Percival gave a scream of fright as Jack went overboard, although he was usually a very self-contained young fellow and not apt to give way to hysterical outbreaks.

It was dark in the cave, but he quickly groped for the torch which Jack had dropped, and cried out: