e edge of the pit jutted out
in a narrow tongue of rock that extended outward for about twenty
feet over the pit.

Joan and Powell had barely taken their place with the other captives
when an abrupt and familiar sound drew their attention to the floor
of the pit some thirty feet beneath them. Its smooth sandy bottom
was clearly visible from where they stood. And there on that sandy
floor were six great gleaming shapes of menace which brought
involuntary gasps of horrified amazement to the captives' lips.

The faint musical tinkling sound as the things moved in occasional
ponderous restlessness was unmistakable. Joan and Powell realized
that the amazing organisms responsible for the mysterious Tinkling
Death were at last before them.

The things were giant _living_ crystals--great silvery
semi-transparent shapes nearly ten feet in height, their faceted
sides pulsing in sinister and incredible life as they gleamed in
unearthly beauty beneath the blazing rays of the red moon!

Near the center of each of the giant crystals there was visible
through the semi-transparent wall a large inner nucleus of sullen
opalescence that ceaselessly swirled and eddied.

Their powers of movement were apparently limited to a slow,
ponderous, half-rocking, half-rolling progress on their heavy
rounded bases. They were now grouped in a rough semicircle just
under the edge of the rocky projection that extended out over the
pit. The opalescent nucleus in every silvery faceted form seemed to
be "watching" with frightening intensity the figures on the pit's
edge above them.

* * * * *

There was no mistaking the meaning of the scene. The giant
carnivorous crystals had obviously been lured from their normal
habitat in Arret's red vegetation, and established there in the big
pit by the rat-men to act as principals in their primitive religious
ceremonies.

Those Devil Crystals waiting down there on the pit's floor were
waiting to be fed--and the small group of captives, rat-men and
human beings, were to be the feast!

Utterly sick at heart, Powell wondered if they would at least be
given the boon of a merciful death before being hurled over the
brink to those lurking shapes. He was not left long in doubt.

At a shrill command from the rat-king the guards closed in upon the
captives and herded two of the bound rat-men from among them. A
guard placed to the lips of each of the captive brutes a small cup
cont