The night was on them, where they crouched in a cave above a swiftly flowing river. Kirby, rifle across his knees, sat peering out across the black, invisible stretches of the forest. His nostrils quivered to this mingled smells of fresh growth and fetid decay of the grotesque land. In his ears shrilled the creaking and scraping of insects, the flap of unseen wings, the distant bellowing grunt of some unseen, unknown animal. "I cannot sleep," Ivana said presently, from back in the cave. "Hush," he whispered, "you will wake Nini." "But I am already awake!" came her answer. "I--I cannot forget the white snakes which slid from that tree when you tried to cut firewood." "Hush," Kirby murmured again. "Presently the moon will rise on the earth above, and light will come here. Even if the jungle is terrible, were you not born with courage? Go to sleep now, both of you, because you must relieve me soon." As silence fell again, he knew that the real thing behind their nervousness was their ghastly doubt about what the night was bringing to Naida. But none of them spoke of Naida. So sickening were the possibilities that Kirby would not permit conjecture to occupy even his mind when, at length, the sound of even breathing told him that Nini and Ivana slept. After dreary passing of an hour, a faint light grew over the jungle, silver and clear, and Kirby let his mind run back to the two deserted ape-men communities which they had found and searched before dusk sent them to the cave. From the signs of hasty departure, it looked as though a far-reaching order had taken the brutes away from their dwellings, and sent them--somewhere. That somewhere seemed likely to be the great central community which Ivana said was rumored to exist in the far reaches of the Rorroh. The problem was how to locate the community through the hideous country. But Kirby presently drove the question from his head. To-morrow's evils could best be faced when morrow dawned. * * * * * Enough light had grown now so that the swirling bosom of the river, and a strip of sand directly below the cliff in which their cave was set, were visible. As Kirby let his eyes wander to the lush growth beyond the sand, he heard something which made him stir uneasily. Some creature which suggested power and hugeness immeasurable was moving there. The brush parted, and he saw plainly an animal with the bulk of a two-story house. On two feet the nightmare thing stood, as lightly as a cat, and then came down on all four feet as it ambled out on the sand and extended into the lapping river a tremendous beak studded with teeth. A smell of crushed weeds and the musty odor like that of a lion house filled the night. The tyranosaur--it was more like a tyranosaur than anything else--breathed heavily and guzzled in great mouthfuls of water.