He stumbled blindly forward, groping for he knew not what till suddenly the floor beneath him tilted and he shot downward into a darkness even more utter than that above. He felt his body strike a smooth surface and he realized that he was hurtling downward as through a polished chute while from above there came the mocking tones of a taunting laugh and the voice of Lu-don screamed after him: "Return to thy father, O Dor-ul-Otho!" The ape-man came to a sudden and painful stop upon a rocky floor. Directly before him was an oval window crossed by many bars, and beyond he saw the moonlight playing on the waters of the blue lake below. Simultaneously he was conscious of a familiar odor in the air of the chamber, which a quick glance revealed in the semidarkness as of considerable proportion. It was the faint, but unmistakable odor of the GRYF, and now Tarzan stood silently listening. At first he detected no sounds other than those of the city that came to him through the window overlooking the lake; but presently, faintly, as though from a distance he heard the shuffling of padded feet along a stone pavement, and as he listened he was aware that the sound approached. Nearer and nearer it came, and now even the breathing of the beast was audible. Evidently attracted by the noise of his descent into its cavernous retreat it was approaching to investigate. He could not see it but he knew that it was not far distant, and then, deafeningly there reverberated through those gloomy corridors the mad bellow of the GRYF. Aware of the poor eyesight of the beast, and his own eyes now grown accustomed to the darkness of the cavern, the ape-man sought to elude the infuriated charge which he well knew no living creature could withstand. Neither did he dare risk the chance of experimenting upon this strange GRYF with the tactics of the Tor-o-don that he had found so efficacious upon that other occasion when his life and liberty had been the stakes for which he cast. In many respects the conditions were dissimilar. Before, in broad daylight, he had been able to approach the GRYF under normal conditions in its natural state, and the GRYF itself was one that he had seen subjected to the authority of man, or at least of a manlike creature; but here he was confronted by an imprisoned beast in the full swing of a furious charge and he had every reason to suspect that this GRYF might never have felt the restraining influence of authority, confined as it was in this gloomy pit to serve likely but the single purpose that Tarzan had already seen so graphically portrayed in his own experience of the past few moments.