vader.

Then, with the heavy weapon again in his hand, he remorselessly
charged his remaining foe. The Centaurian's tube flashed in a
veritable hail of hurtling violet bolts, but Dixon caught the flashes
upon his shield and closed grimly in.

One final leap brought him to close quarters. The heavy ax whistled
through the air in a single mighty stroke that cleft the Centaurian's
frail body nearly in two.

Then Ruth's excited scream came again. "Bruce--the other one! Get it
quick!"

* * * * *

Dixon turned. The wounded invader, taking advantage of their
preoccupation in the final struggle with its mate, had dragged its
crippled body over to the instrument enclosure. Dixon staggered toward
it as fast as his half-paralyzed muscles would permit.

He was just too late. The Centaurian jerked a lever home a fraction of
a second before Dixon's smashing ax forever ended his activities. The
lever's action upon the pen of inert hybrids was immediate.

The sweeping lances of light vanished in a brief sheet of vivid flame
which kindled the dark globes on the hybrids' gruesome heads to steady
opalescence--and the dread horde came to life! Sprawling from the pen,
they came scuttling toward Dixon in a surging flood--a scene out of a
nightmare.

Dixon faced the oncoming horde in numb despair, knowing that his
nearly-paralyzed body had no chance in flight. Then, just as the
hybrids were nearly upon him, he heard Ruth's encouraging voice again.

"There's still one chance left, Bruce," she cried, "and I'll take it!"

Dixon turned. Ruth had in her hand the tiny contact grenade he had
given her for a last emergency. She snapped the safety catch on the
little bomb, then hurled it squarely at the giant opalescent globe
looming close beside her.

There was a terrific explosion and the great globe shattered to atoms.
Apparently stunned by the concussion but otherwise unhurt, Ruth was
flung clear of the wreckage.

With the shattering of the central globe the strange life force of the
hybrid horde vanished instantly and completely. Midway in their rush
they sprawled inert and dead, with their outstretched legs so close to
Dixon that he had to step over one or two to get clear.

* * * * *

Dixon's brain reeled in the reaction of relief from the horde's
hideous menace. Then he grimly fought to clear his fast-numbing senses
long enough for the one final task that he knew m