The gryfs below raised their heads and looked in the direction of the interruption. One of them made a low, rumbling sound in its throat. It was not a bellow and it did not indicate anger. Immediately the "Whee-oo!" responded. The gryfs repeated the rumbling and at intervals the "Whee-oo!" was repeated, coming ever closer.

Tarzan looked at Pan-at-lee. "What is it?" he asked.

"I do not know," she replied. "Perhaps a strange bird, or another horrid beast that dwells in this frightful place."

"Ah," exclaimed Tarzan; "there it is. Look!"

Pan-at-lee voiced a cry of despair. "A Tor-o-don!"

The creature, walking erect and carrying a stick in one hand, advanced at a slow, lumbering gait. It walked directly toward the gryfs who moved aside, as though afraid. Tarzan watched intently. The Tor-o-don was now quite close to one of the triceratops. It swung its head and snapped at him viciously. Instantly the Tor-o-don sprang in and commenced to belabor the huge beast across the face with his stick. To the ape-man's amazement the GRYF, that might have annihilated the comparatively puny Tor-o-don instantly in any of a dozen ways, cringed like a whipped cur.

"Whee-oo! Whee-oo!" shouted the Tor-o-don and the GRYF came slowly toward him. A whack on the median horn brought it to a stop. Then the Tor-o-don walked around behind it, clambered up its tail and seated himself astraddle of the huge back. "Whee-oo!" he shouted and prodded the beast with a sharp point of his stick. The GRYF commenced to move off.

So rapt had Tarzan been in the scene below him that he had given no thought to escape, for he realized that for him and Pan-at-lee time had in these brief moments turned back countless ages to spread before their eyes a page of the dim and distant past. They two had looked upon the first man and his primitive beasts of burden.

And now the ridden GRYF halted and looked up at them, bellowing. It was sufficient. The creature had warned its master of their presence. Instantly the Tor-o-don urged the beast close beneath the tree which held them, at the same time leaping to his feet upon the horny back. Tarzan saw the bestial face, the great fangs, the mighty muscles. From the loins of such had sprung the human race—and only from such could it have sprung, for only such as this might have survived the horrid dangers of the age that was theirs.

The Tor-o-don beat upon his breast and growled horribly—hideous, uncouth, beastly. Tarzan rose to his full height upon a swaying branch—straight and beautiful as a demigod—unspoiled by the taint of civilization—a perfect specimen of what the human race might have been had the laws of man not interfered with the laws of nature.