er stopped its advance toward Brand. A raw white spot
as big as a dinner plate leaped into being on one of its enormous hind
legs. It whirled with an ear-splitting hiss, to see what thing was
causing such pain in its rear. The frightful head whipped back at the
end of the long neck, to nuzzle at the seared spot. Then the giant
lizard turned toward Brand again.

A second time Dex pressed the central coil that formed the handle of
the tube, as Greca had showed him how to do. A second time the ray
shot down the field to flick a chunk of flesh weighing many pounds
from the monster's flank. And this time it definitely abandoned the
quarry behind it. With a scream like the keening of a dozen steam
whistles, it charged back over its tracks toward the distant pigmies
that were inflicting such exasperating punishment on it.

Dex swept the tube before him in a short half-circle. A smoking gash
appeared suddenly in the vast fore-quarters of the monster. It
stopped abruptly, its clawed feet plowing along the ground with the
force of its momentum. An instant it stood there. Then, with its head
swinging from side to side and lowered so that its looped neck dragged
on the reddish, dusty ground, it began to back away from the source of
its hurt, bellowing and hissing its rage and bewilderment.

"Brand!" shouted Dex. "This end! Run, while I hold the thing off!"

Brand began to race down the long enclosure, ten feet to a leap. The
great lizard darted after him, like a cat after an escaping mouse; but
a flick of the tube sent it bellowing and screaming back to its
corner.

"Dex!" gasped Brand. "Thank God!"

For a moment he leaned, white and shaken, against the wall. Then Greca
caught his hand in both of hers, and Dex put his arm supportingly
around his shoulder. They retreated back through the doorway behind
them, and slid the bolt across the metal door.

CHAPTER X

_The "Tank Scheme"_

"Thank God you came when you did," repeated Brand. Then, with a moment
in which, figuratively, to get his feet back on earth, the wonder of
Dex's appearance struck him.

"How did you manage to get away?" he asked. "I was sure--I
thought--when they dragged you out of the tower room I wouldn't see
you again--"

Rapidly Dex gave an account of his ordeal in the torture chamber,
telling Brand in a few words how he had attempted to win free of the
Rogans, how he had almost succeeded, only to be caught again and
clamped to the death-plate o