t them
through the thick glass of the bull's-eye the boys beheld the most
hideous sea monster they had yet encountered.

It seemed to be a vast circular mass of flesh, twenty feet in diameter,
and, in the middle were two openings each three feet across. They were
like big holes, and, at the farther end of them could be seen two
unblinking eyes. In the centre was a horrible mouth, armed with a triple
row of teeth.

Down below there was a short body, at the end of which was a smaller
disk, armed with a sharp horny point.

"What is it?" asked Jack in a whisper.

"I don't know," replied Mark.

A moment later Mr. Henderson came up the companionway into the tower. He
caught one glimpse of the monster.

"It is the great sucker of the polar seas!" he exclaimed. "Quick! Speed
up the engine! If that one, and the mates of it, fasten on to us we will
have trouble!"

He pressed the signal that connected with the engine room, and told
Washington to start the engine at its greatest power. The next instant
the ship throbbed and trembled under the vibrations of the big screw.

"We may escape!" cried the professor.

As he spoke the ship seemed to come to a sudden stop. The engine could
still be felt moving, and the big screw still churned the water to foam
in the tunnel, but the craft was stationary.

"We are caught!" exclaimed the professor.

"So we are!"

The windows in the conning tower were darkened. The big sucker had
thrown itself forward and spread itself over the glass, clasping its
horrible form half way about the submarine.

"Let's look at the other windows! There may be only one of the
creatures!" Mr. Henderson exclaimed, as he hurried down the companion
way and into the main cabin. He threw back the slides covering the
glass.

The sight that met his eyes caused him to recoil in horror. There,
pressing their shapes against the steel sides, and over the bull's-eyes
of the ship were two more of the gigantic suckers!

The ship had now ceased to move, and Washington, in the engine room,
feeling that something was wrong, had shut off the power. The
adventurers were caught in a trap more terrible than that of the ice,
the volcanic mountain, or the Sargasso Sea. It was a trap from which
they might never escape.

The suckers, thinking the submarine was perhaps a species of fish, like
themselves, and one of their enemies, had fastened on it their fatal
vice-like grip. To move through the water, with the weight of