Where the underbrush was heaviest, where fallen trees blocked the way, he led the footsteps of the creature below them; but all to no avail. When they reached the opposite side of the gorge the gryf was with them.

"Back again," said Tarzan, and, turning, the two retraced their high-flung way through the upper terraces of the ancient forest of Kor-ul-gryf. But the result was the same—no, not quite; it was worse, for another gryf had joined the first and now two waited beneath the tree in which they stopped.

The cliff looming high above them with its innumerable cave mouths seemed to beckon and to taunt them. It was so near, yet eternity yawned between. The body of the Tor-o-don lay at the cliff's foot where it had fallen. It was in plain view of the two in the tree. One of the gryfs walked over and sniffed about it, but did not offer to devour it. Tarzan had examined it casually as he had passed earlier in the morning. He guessed that it represented either a very high order of ape or a very low order of man—something akin to the Java man, perhaps; a truer example of the pithecanthropi than either the Ho-don or the Waz-don; possibly the precursor of them both. As his eyes wandered idly over the scene below his active brain was working out the details of the plan that he had made to permit Pan-at-lee's escape from the gorge. His thoughts were interrupted by a strange cry from above them in the gorge.

"Whee-oo! Whee-oo!" it sounded, coming closer.

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.