The great reptile he had just seen was a "thunder lizard," or brontosaurus.

Renny recalled they were popularly supposed to be peaceful giants, haunting the water and feeding on lake plants and shore growth. The theory held by scientists is that they were not meat devourers.

Renny had no desire to test the accuracy of that theory. Compared to the thunder lizard in size, he was like a mouse beside a fat hog. He didn’t know but what the beast might decide to try a man for a change of diet.

So Renny ran for all he was worth. The thunder lizard, apparently curious or playful, lumbered after him. The earth shook in a pronounced manner under its incalculable weight.

Quitting the trail opened by the armor-plated monster which had brought him here, Renny dived into the tangled vegetation. He lost his hundreds of tons of gamboling pursuer.

"Whew!" He mopped his forehead with both sleeves. "Whew!"

He felt his way onward, machine gun ready in one hand. So dark had become the night that he could not even see the weapon he held. He halted often to listen to the awful uproar of the night.

Once a nocturnal fray broke out near by, and the course of the battle brought it directly for Renny! He fled madly. Strong in his nostrils was the fetid, near-suffocating odor of a great carnivore. He knew here was genuine danger! It was another of the monster killers of prehistoric ages, a tyrannosaurus. His parachute had fallen upon one of those!

Renny crept away, marveling at the variety of ear-splitting sounds emitted by the weird beasts of the crater. He reasoned the things could see somewhat in the darkness. He had noticed the eyes of the reptiles were particularly fitted for vision in restricted light. But in darkness such as this, it was impossible for them to see much. They must hunt largely by the sense of hearing, perhaps some of them with the organ of smell.

"What a place to have to live in!" he muttered.

It was only a moment later that fresh disaster overtook him.

Came a great fluttering sound from above his head! It was as if some one were shaking a large carpet up there.

"What the — " Then Renny knew what it was. One of the flying reptiles! A pterodactyl — one of the horrors which had disabled their plane!

Wildly, Renny flung up his gun.

But before he could pull the trigger, the gruesome marauder was upon him!

RENNY now got one of the few pleasant surprises of the night. He realized this aлrial, batlike thing was much smaller than the one which had assailed the plane. Probably it was a chick of the species!

Evading the snapping, toothed beak, Renny clutched with his powerful hands. He got fistfuls of the revolting, membranous wings. The stuff felt like rubber. It was clammy. And a noisome stench accompanied the reptile.

The beak crunched. It took off the entire back of Renny’s coat!

Grasping again, Renny secured a hold on the fearsome head. The body of this pterodactyl was about the size of an ostrich’s. Renny put forth a superhuman effort, tossing himself about violently. He succeeded at last in what he was trying to do. He wrung the neck of the flying reptile!

But the thing did not die immediately! It whipped about, as tenacious of life as the tail of a snake. But Renny had at least stopped its attack. The slow death meant the creature scarcely had a definite brain center. Possibly it depended on its brain so little that it could even go on living for a time with that organ entirely removed!

"What a place this is!" Renny muttered.

He lifted the expiring pterodactyl. Its lightness was astounding.

"Bones hollow and filled with air!" decided Renny, drawing on his scant knowledge of prehistoric life forms.

He tossed the flying reptile away, took a step sidewise — and froze in horror!

Another specimen of monster dinosaur was approaching. The struggles of the dying air monster were attracting it!

Renny retreated hastily. He tried to be silent. But this was impossible in the abyss of darkness.

He heard the heavy steps of the approaching giant. They sank noisily into the spongy earth, so vast was the weight upon them. At the dying pterodactyl, the steps stopped.

A ghastly crunching of flesh and popping of chewed bones indicated the flying reptile was being devoured.

Renny quickened his pace, thinking to escape while the beast was occupied. But he had the misfortune to stumble. His shoulder brushed a bush. There was considerable noise.

The beast charged!

The rapidity with which it came showed Renny he could not hope to outrun it. He tried a desperate experiment. Halting, he quickly wrenched off what of his coat had remained after the bite delivered by the gargantuan aлrial reptile.

Renny carried a waterproof cigarette lighter, although he did not smoke. It was handier than matches. He plucked it out of a pocket. Its tiny flame sprang up. He set fire to his fragment of coat.

Whirling the coat around his head speeded the fire. In an instant it was a sizable brand.

He flung it in the face of the charging monster!

AS the flaming cloth gyrated through the air, Renny got a fleeting view of the repellent dinosaur stalking him.

It had a lizardlike body, armored with great bony plates. It traveled on all fours. Its head was uncouth as that of a mud turtle, but more than a yard in length. The low-slung carcass of the creature, although thin from side to side, was very high.

Most striking of its characteristics was the double row of huge, horny plates standing on edge down its back. These looked like two lines of monster saw teeth.

The name of the thing — stegosaur — escaped Renny. Anyway, what interested him at the moment was its reaction to the fire. Would it flee?

It didn’t!

Renny realized the colossal reptile did not have the brains to recognize the fire as danger. Pivoting, he ran with all his speed.

Ferns whipped him. The needled tips of coniferous shrubs gouged at his eyes. Lianas held him back. He tore at the growth with his powerful hands. Suddenly, penetrating that jungle became like burrowing through a stack of green, wet hay.

Behind him thundered the leviathan of the reptilian world. It seemed to gain as though he were standing still. Great knots of the soggy earth, dug up by its churning feet, fell noisily.

Renny had been in few tighter spots in his eventful life. He could not outrun this thing. In the darkness, he could not hide effectively — it would smell him out.

It was now no more than twice Renny’s own length behind him!

And Renny stumbled and fell!

That fall was his salvation. A deep trench had brought him down. Evidently it had been opened by the snout of some tremendous rooting dinosaur.

Renny rolled into the trench!

The pursuing reptile passed over him! It was as though an earthquake had laid upon the surrounding ground. The earth walls of the trench gave under the vast weight. They caved.

Renny was buried by the earth!

He was drawing in a breath of relief when the cave-in came. So he had a quantity of air in his lungs. He held it there. Not a muscle did he move.

The clumsy reptile turned slowly and came back. The stupid thing did not know what had become of its quarry. It tramped the vicinity for a time, searching.

Earth pressed in more tightly as it strode somewhere near Renny.

The big-fisted engineer had held his breath about as long as he could. His lungs felt lead-filled. His ears sang.

The giant dinosaur lumbered majestically away. It had given up. The earth covering Renny had kept the reptile from scenting him.

In a near frenzy, such torture was he suffering, Renny squirmed about. He threshed in the soft earth. For a moment he thought he was entombed alive. But the convulsive effort this belief made him put forth, brought him near the surface.