It recoiled and then folded once more, and Kay's mighty sweeps were slashing phantom limbs from phantom bodies; and lopping off tentacles that curled and coiled, and put forth caricatures of hands and fingers, and then, uniting with other slashed off tentacles, began to mould themselves into the likeness of dwarf monsters. Kay's struggle was like that of a man fighting a fog, for again and again he broke through the wall, and always it reunited. And behind it another wall of protoplasm was pressing forward, and on another side a wall was drifting up. As Kay stopped, panting, and momentarily free, Ruth saw that they were almost encircled. She saw the nature of that fight. Inevitably that wall would close about them; and, though the bones of last year's victims had been gathered up and carried away by the Federation, she guessed what would occur. She ran to Kay and dragged him back through the closing gap. It met behind them, and again they stood face to face with the devils. Only this time, instead of a wall of protoplasm, it was a veritable mountain that confronted them, and there could be no more breaking through. Kay thought afterward that the one touch of absolute horror was that the reforming monsters, the young ones growing visibly before his eyes, had the gamboling instinct of young lambs or other creatures. They were much more lively than the parent creatures. * * * * * By this time perhaps a third of the space within the electrified lines had been occupied by the devils. The wall was slowly and sluggishly advancing, and a fresh infiltration was drifting in on another side. As the victims were pressed closer and closer together in their flight, half of them seemed to go insane. They raced to and fro, laughing and screaming, flinging their arms aloft in extravagant gestures. One young fellow, rushing across the ground, hurled himself like a bolt from a catapult into the heart of the grisly mass, which opened and received him. There was a struggle, a convulsion; then the mass moved on. Kay wiped his ax. He stood beside Ruth, gathering strength and breath to fight again. What else was there to do? Suddenly a humming sound came to his ears. Still some little distance from the monsters, he glanced back. The victims were shouting, staring upward. Over the tops of the jungle trees Kay saw a second airplane flying toward them, a larger one than the plane which he had flown. It opened its helicopter wings and drifted downward. Kay saw a single pilot, and, in the baggage compartment something that at first he did not recognize. Then he recognized both this object and the aviator. "It's Cliff," he whispered hoarsely. "He's brought the top!" * * * * *