An idea occurred to me, suggested by what Thuvia had just said.

"Why not take a number of banths and set them loose before us above ground?" I asked.

Thuvia laughed.

"It would distract attention from us, I am sure," she said.

She commenced calling in a low singsong voice that was half purr. She continued this as we wound our tedious way through the maze of subterranean passages and chambers.

Presently soft, padded feet sounded close behind us, and as I turned I saw a pair of great, green eyes shining in the dark shadows at our rear. From a diverging tunnel a sinuous, tawny form crept stealthily toward us.

Low growls and angry snarls assailed our ears on every side as we hastened on and one by one the ferocious creatures answered the call of their mistress.

She spoke a word to each as it joined us. Like well-schooled terriers, they paced the corridors with us, but I could not help but note the lathering jowls, nor the hungry expressions with which they eyed Tars Tarkas and myself.

Soon we were entirely surrounded by some fifty of the brutes. Two walked close on either side of Thuvia, as guards might walk. The sleek sides of others now and then touched my own naked limbs. It was a strange experience; the almost noiseless passage of naked human feet and padded paws; the golden walls splashed with precious stones; the dim light cast by the tiny radium bulbs set at considerable distances along the roof; the huge, maned beasts of prey crowding with low growls about us; the mighty green warrior towering high above us all; myself crowned with the priceless diadem of a Holy Thern; and leading the procession the beautiful girl, Thuvia.

I shall not soon forget it.

Presently we approached a great chamber more brightly lighted than the corridors. Thuvia halted us. Quietly she stole toward the entrance and glanced within. Then she motioned us to follow her.

The room was filled with specimens of the strange beings that inhabit this underworld; a heterogeneous collection of hybrids-the offspring of the prisoners from the outside world; red and green Martians and the white race of therns.

Constant confinement below ground had wrought odd freaks upon their skins. They more resemble corpses than living beings. Many are deformed, others maimed, while the majority, Thuvia explained, are sightless.

As they lay sprawled about the floor, sometimes overlapping one another, again in heaps of several bodies, they suggested instantly to me the grotesque illustrations that I had seen in copies of Dante's INFERNO, and what more fitting comparison? Was this not indeed a veritable hell, peopled by lost souls, dead and damned beyond all hope?

Picking our way carefully we threaded a winding path across the chamber, the great banths sniffing hungrily at the tempting prey spread before them in such tantalizing and defenceless profusion.

Several times we passed the entrances to other chambers similarly peopled, and twice again we were compelled to cross directly through them. In others were chained prisoners and beasts.

"Why is it that we see no therns?" I asked of Thuvia.

"They seldom traverse the underworld at night, for then it is that the great banths prowl the dim corridors seeking their prey. The therns fear the awful denizens of this cruel and hopeless world that they have fostered and allowed to grow beneath their feet. The prisoners even sometimes turn upon them and rend them. The thern can never tell from what dark shadow an assassin may spring upon his back.

"By day it is different. Then the corridors and chambers are filled with guards passing to and fro; slaves from the temples above come by hundreds to the granaries and storerooms. All is life then. You did not see it because I led you not in the beaten tracks, but through roundabout passages seldom used. Yet it is possible that we may meet a thern even yet. They do occasionally find it necessary to come here after the sun has set. Because of this I have moved with such great caution."

But we reached the upper galleries without detection and presently Thuvia halted us at the foot of a short, steep ascent.

"Above us," she said, "is a doorway which opens on to the inner gardens. I have brought you thus far. From here on for four miles to the outer ramparts our way will be beset by countless dangers. Guards patrol the courts, the temples, the gardens. Every inch of the ramparts themselves is beneath the eye of a sentry."

I could not understand the necessity for such an enormous force of armed men about a spot so surrounded by mystery and superstition that not a soul upon Barsoom would have dared to approach it even had they known its exact location. I questioned Thuvia, asking her what enemies the therns could fear in their impregnable fortress.

We had reached the doorway now and Thuvia was opening it.

"They fear the black pirates of Barsoom, O Prince," she said, "from whom may our first ancestors preserve us."

The door swung open; the smell of growing things greeted my nostrils; the cool night air blew against my cheek. The great banths sniffed the unfamiliar odours, and then with a rush they broke past us with low growls, swarming across the gardens beneath the lurid light of the nearer moon.

Suddenly a great cry arose from the roofs of the temples; a cry of alarm and warning that, taken up from point to point, ran off to the east and to the west, from temple, court, and rampart, until it sounded as a dim echo in the distance. The great Thark's long-sword leaped from its scabbard; Thuvia shrank shuddering to my side.

"What is it?" I asked of the girl.

For answer she pointed to the sky.

I looked, and there, above us, I saw shadowy bodies flitting hither and thither high over temple, court, and garden.

Almost immediately flashes of light broke from these strange objects. There was a roar of musketry, and then answering flashes and roars from temple and rampart.

"The black pirates of Barsoom, O Prince," said Thuvia.

In great circles the air craft of the marauders swept lower and lower toward the defending forces of the therns.

Volley after volley they vomited upon the temple guards; volley on volley crashed through the thin air toward the fleeting and illusive fliers.

As the pirates swooped closer toward the ground, thern soldiery poured from the temples into the gardens and courts. The sight of them in the open brought a score of fliers darting toward us from all directions.

The therns fired upon them through shields affixed to their rifles, but on, steadily on, came the grim, black craft. They were small fliers for the most part, built for two to three men. A few larger ones there were, but these kept high aloft dropping bombs upon the temples from their keel batteries.

At length, with a concerted rush, evidently in response to a signal of command, the pirates in our immediate vicinity dashed recklessly to the ground in the very midst of the thern soldiery.

Scarcely waiting for their craft to touch, the creatures manning them leaped among the therns with the fury of demons. Such fighting! Never had I witnessed its like before. I had thought the green Martians the most ferocious warriors in the universe, but the awful abandon with which the black pirates threw themselves upon their foes transcended everything I ever before had seen.

Beneath the brilliant light of Mars' two glorious moons the whole scene presented itself in vivid distinctness. The golden-haired, white-skinned therns battling with desperate courage in hand-to-hand conflict with their ebony-skinned foemen.

Here a little knot of struggling warriors trampled a bed of gorgeous pimalia; there the curved sword of a black man found the heart of a thern and left its dead foeman at the foot of a wondrous statue carved from a living ruby; yonder a dozen therns pressed a single pirate back upon a bench of emerald, upon whose iridescent surface a strangely beautiful Barsoomian design was traced out in inlaid diamonds.