As he stood there, he became aware of two circles of rats forming at the base of the mound, each circle consisting of about a thousand animals. They began a weird dance, moving around the raised dais of bones counter-clockwise. The tail of each rat was gripped in the mouth of the following beast, thus forming a continuous chain.

There was no doubt that the earthman was in the center of a weird ritual. While he was ignorant of the exact nature of the ceremony, he had little doubt as to its final outcome. The countless barren skulls, the yellowed ones that filled the cavern were mute, horrible evidence of his final fate.

Where did the rats get all the bodies from which the skulls were obtained and why were the tops of those skulls missing? The City of Korvas, as every Martian schoolboy knew, had been deserted for a thousand years; yet many of the skulls and bones were recently picked clean of their flesh. Carter had seen no evidence in the city of any life other than the great white apes and the mysterious giant, and the rats themselves. However, there had been the woman's scream that he had heard earlier. This thought accentuated his ever-present anxiety over Dejah Thoris's safety and whereabouts.

This delay was tormenting. As the circles of rats closed in about him, the earthman's eyes eagerly searched for some avenue of escape.

The rats circled slowly, watching their king who rose to his hind legs stamping his feet, thumping his tail. The mound of skulls echoed hollowly.

Faster danced the king and faster moved the circles of rats drawing ever closer to the mound.

The closer rats shot hungry glances at the earthman. Carter smiled grimly and gripped his sword more tightly. Strange that they should let him retain it.

More than one of the beasts would die before he was overcome, and the king would be the first to go. There was no doubt that he was to be sacrificed to furnish a gastronomic orgy.

Suddenly the king stopped his wild gyrations directly in front of Carter. The dancers halted instantly, watching, waiting.

A strange, growling squeal started deep in the king's throat and grew in volume to an ear-piercing shriek. The King of Rats stepped over the ring of skulls and advanced slowly toward Carter.

Once again the earthman glanced about seeking some means of escape from the mound. This time he looked up. The ceiling was at least fifty feet away. No native-born Martian would ever consider escaping in that direction.

But John Carter had been born on the planet Earth, and he had brought with him to Mars all the strength and agility of a trained athlete.

It was upon this, combined with the lesser gravity of Mars, that the earthman made his quick plan for the next moment. Tensely he waited for his opportunity. The ceremony was nearly concluded. The king was baring his fangs not a foot from Carter's neck.

The earthman's hand tightened on his sword-hilt; then the blade streaked from its scabbard. There was a blur of motion and a sickening smack. The king's head flew into the air and then rolled away, bouncing down the mound.

The other beasts beneath were stunned into silence, but only momentarily. Now, squealing wildly, they swarmed up the mount intent on tearing the earthman to pieces.

John Carter crouched and with a mighty leap his earthly muscles sent him shooting fifty feet up into the air.

Desperately he clutched and held to a hanging stalactite. Soon he was swinging on the hanging moss to the vast upper reaches of the cavern.

Once he looked down to see the rats milling and squealing in confusion beneath. One other fact he noted, also. Apparently there was only one means of entrance or exit into the dungeon that formed the rats' underground city, the same tunnel through which he had first been dragged.

Now, however, the eartbman was intent upon finding some means of exit in the ceiling above.

At last he found a narrow opening; and plunging through a heavy curtain of moss Carter swung into a cave. There were several tunnels branching off into the darkness, most of them thickly hung with the sticky webs of the great Martian spider. They were evidently parts of a vast under-ground network of tunnels that had been fashioned long ages ago by the ancients who once inhabited Korvas.

Carter was ready with his blade for any encounter with man or beast that might come his way; and so he started off up the largest tunnel.

The perpetually burning radium light that had been set in the wall when the tunnel was constructed furnished sufficient illumination for the earthman to see his way quite clearly.

Carter halted before a massive door set into the end of a tunnel. It was inscribed with hieroglyphics unfamiliar to the earthman.