th a rain of lead from one of the
automatics, holding the other as a reserve. The heavy bullets plowed
murder into the close-packed furry bodies. The charge wavered
momentarily. Then Powell felt Joan tugging frantically at his arm.

"Larry, the rocks under us are crumbling!" she cried. "We'll be
hurled down into the pit!"

Even as she spoke, Powell felt the narrow strip of rock under them
quiver and settle. He looked quickly down. All along its length, the
narrow rocky projection, weakened by their weight, was breaking
swiftly away from the pit's edge. And on the floor of the pit below
them the two waiting Devil Crystals moved with musical, tinkling
sounds as they waited restlessly for their prey to fall among them.

The horde of rat-men rallied and swept on forward in a wave that
nothing could have stopped this time--but their charge was too late.
The entire rocky projection collapsed with a final sickening lurch,
and slid to the pit's floor, carrying Joan and Powell with it in a
miniature avalanche of rocky rubble.

* * * * *

Even in the chaos of their wild descent, Powell retained his grip
upon the loaded automatic in his hand. They struck the bottom and
staggered half-dazed to their feet, to confront the two crystalline
monsters rocking on their rounded bases scarcely ten feet away.

The fatal cone-shaped projection was already beginning to form upon
the silver-faceted side of the nearest Devil Crystal. Before the
lance-like arm of crystal could flash outward, Powell sent two
bullets crashing into the crystal's side just over the opalescent
nucleus.

The leaden missiles caromed harmlessly off, as though they had
struck armor-plate, but the nucleus clouded momentarily and the
cone-shaped projection dissolved back into the side.

With lightning speed Powell shifted his aim to the other crystal
just as its partly-formed arm was flashing toward them. His bullet
crashed into the silvery side squarely over the nucleus. Again the
bullet's effect was the same. This crystal nucleus clouded murkily,
and the lance-like arm telescoped back into the faceted bulk.

But the effect of the bullets was only momentary. Swiftly the nuclei
of both crystals cleared. A deep blue film, apparently protective in
nature, formed between the outer wall and each nucleus. The cones
budded, and again the arms started forth.

Powell fired again, and this time uselessly. His bullet struck
squarely, but th