Presently the light dipped downward and vanished. We saw that this figure we were following had entered a black cave-mouth—an opening which ran diagonally down into a slimy bank of mud. And we saw, too, that the points of steady light which had first attracted our attention were the reflected glow of illumination from somewhere beneath the sea floor. Silently we slipped into the cave-mouth. The moving light was down there: then abruptly it disappeared. “Wait!” whispered Caan. “Go slower!” We advanced cautiously—and came again to a hedge of coral which impeded our passage. But this barrier we saw at once was artificial. It was the crude doorway—created by human intelligence and industry—which barred the creatures of the wild from entering. We threaded our way through it. Any one of those sea-monsters could have battered it down had he known his strength. But such a knowledge is given only to Man. Beyond the barrier the dim glow of a diffused green light became visible. We edged cautiously forward, turned a corner, came suddenly to a ledge, and stopped—breathless, with wildly beating hearts. We were looking down from near the ceiling of a cave. The water filling it was lighted with a pale green radiance, that lent a ghastly, wavering unreality to the scene. The cave might have been several hundred feet in width—nearly circular—and shallow, a hundred feet perhaps from floor to ceiling. The opposite wall to us was plainly visible. It was gouged out with niches in ranks and tiers—shallow ledges like the houses of your ancient, most primitive “Cliff-dwellers.” We could see little family groups squatting on many of them—humans, not unlike the Marinoids in form—men, and women, and children. But it was none of this that caused our hearts to leap so wildly. The floor of this community house was at the moment crowded with human figures. The figure we had followed in was swimming downward to join them. On a raised platform—a shelf of ooze at the side and bottom of the cave—several old men were sitting. They were not Marinoids—but they seemed to differ principally in the eyes, which were much larger and more vacant, and in the pallid, ghastly whiteness of the puffy flesh of their bodies. On the same platform stood Og! He was gazing down at the throng of people before him—haranguing them. His voice reached us—not Marinoid words, but enough like them—a corruption—to make them intelligible to us. All this we saw at a brief glance. And the crowning thing: On the platform also, between Og and the white old men, my Nona was sitting with her arms bound at her sides! My Nona, beautiful as always, pink skin, blue eyes and golden hair—so vivid amid that pallid, ghastly throng! And she was unharmed—with spirit unbroken—I could see that by the flash of her eyes, her scornful, unwavering gaze as she leveled it at the puffy white faces staring up at her. My Nona! * * * * *