s down yet."

Deeper and deeper the lifeboat was dragged by its dreadful opponent,
whose spiked teeth still tore savagely at the tough outer plating of the
craft, until Costigan reluctantly threw in his power switches. Against
the full propellant thrust the monster could draw them no lower, but
neither could the lifeboat make any headway toward the surface. The
pilot then turned on his beams, but found that they were ineffective. So
closely was the creature wrapped around the submarine that his weapons
could not be brought to bear upon it.

"What can it possibly be, anyway, and what can we do about it?" Clio
asked.

"I thought at first it was something like a devilfish, or possibly an
overgrown starfish, but it isn't," Costigan made answer. "It must be a
kind of flat worm. That doesn't sound reasonable--the thing must be all
of a hundred meters long--but there it is. The only thing left to do
that I can think of is to try to boil him alive."

He closed other circuits, diffusing a terrific beam of pure heat, and
the water all about them burst into furious clouds of steam. The boat
leaped upward as the metallic fins of the gigantic worm fanned vapor
instead of water, but the creature neither released its hold nor ceased
its relentlessly grinding attack. Minute after minute went by, but
finally the worm dropped limply away--cooked through and through;
vanquished only by death.

"Now we've put our foot in it, clear to the neck!" Costigan exclaimed,
as he shot the lifeboat upward at its maximum power. "Look at that! I
knew that Nerado could trace us, but I didn't have any idea that _they_
could!"

Staring with Costigan into the plate, Bradley and the girl saw, not the
Nevian sky-rover they had expected, but a fast submarine cruiser, manned
by the frightful fishes of the greater deeps. It was coming directly
toward the lifeboat, and even as Costigan hurled the little vessel off
at an angle and then sped upward into the air, one of the deadly
offensive rods, tipped with its glowing ball of pure destruction,
flashed through the spot where they would have been had they held their
former course.

But powerful as were the propellant forces of the lifeboat and fiercely
though Costigan applied them, the denizens of the deep clamped a tractor
beam upon the flying vessel before it had gained a mile of altitude.
Costigan aligned his every driving projector as his vessel came to an
abrupt halt in the invisible grip of the beam,