The green man was almost of heroic proportions; he was clad in but a breech-clout, and was so broad as to appear squat in stature. He carried a short club, and appeared almost as dumbfounded as the two Americans. A moment he regarded them, then, with a ferocious snarl of rage, he hurled himself upon the startled Ward and half clubbed, half pushed him to the floor. Recovering from his momentary inaction and realizing the danger in which his friend stood, Miles shouted and leaped upon the green man's back, fastening his sinewy fingers about the giant's throat.

But the latter was possessed of incredible strength, and, straightening up, he shook off Miles as a bear might shake off an attacking dog, and threw him heavily to the floor. Then the green giant whirled up his club, and it would have gone hardly with Miles if Ward had not remembered his automatic and fired in the nick of time.

As if poleaxed, the green man fell; and both the adventurers recovered their feet.

"Look out!" shouted Ward.

Through a wide entrance came charging a dozen greenish giants. Miles fired both his pistols. The leader of the greenish men paused in mid-leap, clawing at his stomach.

"This way, Kid!" yelled Ward; "this way!"

Taking advantage of the confusion in the ranks of the attackers, the two sprang to where an exit in the far wall promised an avenue of escape. Down a broad pa.s.sage they rushed. Seemingly the pa.s.sage ended in a cul-de-sac, for a wall of blank whiteness barred further progress. Behind them came charging the greenish giants uttering appalling cries. Desperately the two Americans turned, resolved to sell their lives as dearly as possible; but at that moment happened a sheer miracle. The blank wall divided, revealing a narrow crevice through which they sprang. Noiselessly the crevice closed behind them, shutting out the green pursuers, and a voice said--a voice in precise but strangely accented English:

"We have been expecting you, gentlemen, but--where is Solino?"

Never would Miles and Ward forget the amazement of that moment. They were in a place which looked not unlike a huge laboratory. Then they saw it was a lofty room containing a variety of strange mechanisms.

But it was not on these their eyes focussed. Confronting them in odd wheelchairs, with hairless heads projecting from tubular containers like the one they had seen encasing the man at the control board of the submarines, were all of half a hundred crippled men!

"Good Lord!" exclaimed Miles, "I must be seeing things!"

"Where is Solino?" demanded the voice in strangely accented English.

Ward saw that the question came from an individual in a wheelchair a few feet in front of them.

"Solino is dead," he answered.

"Dead?" A ripple of sound came from the oddly seated men.

"Yes, the submarine car was wrecked in the tunnel, and everyone aboard was killed save us two."

The hairless men looked at one another. "This is Spiro's work," said one of them, still in English; and another said, "Yes, Spiro has done this."

Miles and Ward were recovering somewhat from their initial astonishment. "What place is this?" asked the former.

"This is Apex--or, rather, the Palace of the Heads in Apex."

The Palace of the Heads! The two Americans tried to control their bewilderment.

"Pardon us if we don't understand. Everything is so strange. First the submarine was wrecked. Then we entered the crystal room and the tunnel vanished. We can't understand how this place can be at the bottom of the Atlantic."

"It isn't at the bottom of the Atlantic."

"Not at the bottom? Then where?"

"It isn't," said the voice slowly, "in your world at all."

The import of what was said did not at first penetrate the minds of the Americans. "Not in our world?" they echoed stupidly.

"Come," said the crippled man smiling inscrutably, "you are tired and hungry. Later I shall explain more." His strangely colored eyes bored into their own. "Sleep," said his voice softly, imperatively; and though they fought against the command with all the strength of their wills, heaviness weighted down their eyelids and they slept.

From dreamless sleep they awakened to find that fatigue had miraculously vanished, that their wounds were healed and their bodies and clothes were free of slime and filth. All but one of the crippled men--for so in their own minds they termed the odd individuals--had gone away. That one was the man who had first addressed them.

"Do not be alarmed," he said. "In our own fashion we have given you food and rest and attended to your comfort."

Ward smiled, though a trifle uncertainly. "We are not easily frightened," he replied.

"So! That is good. But now listen: my name is Zoro and I am Chief of the Heads of Apex. Ages ago we Heads lived on a continent of your Earth now known to scholars as Atlantis. When Atlantis sank below the waves--in your sacred book that tragedy is known as the Flood--all but a scattered few of its people perished. I and my companions were among the survivors."

The Americans stared at him unbelievingly. "But that was a hundred thousand years ago!" exclaimed Ward.

"Three hundred thousand," corrected Zoro.

They stared at him dumbly.

"Yes," said Zoro; "it sounds incredible to your ears, but it is true.

Mighty as is the industrial civilization of your day, that of Atlantis was mightier. Of course, the country wasn't then called Atlantis; its real name was A-zooma. A-zooma ruled the world. Its ships with sails of copper and engines of bra.s.s covered the many seas which now are lands. Its airships clove the air with a safety and speed your own have still to attain. The wealth of the world poured into A-zooma, and its rulers waxed vain-glorious and proud. Time after time the enslaved ma.s.ses of A-zooma and of conquered countries rose in great rebellions. Then against them marched the "iron baylas" breathing death and destruction, and from the air mighty ships poured down the yellow fog...."

Zoro paused, but presently went on: "So we ruled--for ten thousand years; until the scientists who begot those engines of destruction became afraid, because the serfs themselves began to build secret laboratories. We of the priesthood of science saw the inevitable disaster. Long ago we had put off our bodies--"

Zoro smiled at the Americans' amazement. "No," he said, "I am not a cripple in a wheelchair. This tubular container holds no fleshly body.

Inside of it is a mechanical heart which pumps artificial blood--blood purified by a process I will not describe--through my head. It also contains certain inner devices under my mental control, devices that take the place of human hands and feet. Only by accident or through lack of certain essentials can I die."

His listeners stared at him in awe. "You mean," faltered Miles, "that save for your head you are all--machine?"

"Practically, yes. We priest-scientists of the Inner Mystery prolonged life in such fashion. I was three thousand years old when--But enough!

I will not weary you with a recital of how the slaves burrowed the bowels of A-zooma and of how the masters loosed against them the forces of the atom. Suffice it to say that on an island we built our vast system of buildings--or tunnel as you choose to call it--and sealed them away from the outside world, entrance being made by submarines through automatically controlled locks.

"At about this time our experiments opened up another realm of existence, manifesting at a vibratory rate above that of earth. To this new realm we brought workers who built the City of Apex and the palace you are in. But, unfortunately, we brought with us no weapons of offense, and in the new world we had neither the material nor the delicate mechanisms and factories to reproduce them. However, for countless ages there was no rebellion on the part of the workers who, even in A-zooma, had worshipped us as G.o.ds. They were born, grew old and died, but we abode forever. Besides, in the City of Apex they were freer than they had ever been before, merely having to furnish our laboratories with certain raw materials and the wherewithal to sustain the blood supply on which our lives depend. But, of late, they have made common cause with the original inhabitants of this plane, the green men--"

The green men! As if the words were a signal, a dreadful thing happened. Out of a far shadow leaped a lean and hideous monster. To Miles' startled eyes it seemed to grow as it leaped. Thin, unbelievably thin it was, yet swelling at the head. From between two goggle-eyes writhed a rope-like trunk. Twelve feet in the air its head towered over Zoro. "Look out!" screamed the American.

Zoro's chair seemed to jump. Too late! Around the tubular container wrapped the snake-like trunk, plucking the wheelchair and its occupant from the floor and dangling them high in air. "Shoot!" cried Zoro.

Miles shot. His bullet ploughed through the unbelievably thin body and ricochetted from a pillar beyond. Ward fired with better effect. One of the goggle eyes spattered like gla.s.s. Under a fusillade of bullets the monster wilted, giving expression to a weird, shrill cry. Zoro dangled head downwards. To drop from such a height on his skull would probably be fatal.

But the monster did not drop him. Instead, in its death agony, its grip tightened, and the Americans witnessed an incredible sight.

Before their very eyes the monster began rapidly to shrink. Its tenuous body telescoped together, becoming thinner and thinner in the process, until on the floor there lay the lifeless body of a snake-like creature not more than six inches in length!

"Good Lord!" breathed Miles.