Stanley quickly looked upward. What he saw made him gasp. A massive head was clearly outlined against the dark rock of the wall, and a pair of eyes, blazing with a green fire, seemed to pierce him through. “The guns, the guns; quick!” he panted, “before it springs. Don’t mind the one below----” Ted was tugging at his weapon. “I can’t. I can’t point it straight up. The angle is too great.” “Kneel down. I will rest it on your shoulder.” Stanley pulled one of the guns from its mount. The great head was now hanging over the edge of the shelf on which the creature stood, not ten feet above them, and from it came a rumbling growl accompanied by a clicking and champing of strong teeth. Ted had dropped to his knees. Stanley was flat on his back trying to bring the bead through the ring sight of the gun. But the high lights and shadows were deceptive, and before he could align the sights the glowing eyes had vanished again. The tiger had drawn back for the spring. “Back! Flatten yourself against the wall,” he shouted, throwing himself against the face of the cliff and dragging Ted with him. Something whizzed through the air; there came a crunching thud, and then a roar that seemed to make the earth tremble shattered the death-like silence that had reigned in the crater. An instant later a huge, dark form catapulted past the crouching men, heavily struck the edge of the narrow shelf, and fell to the ground with a crash. Something had gone awry; either the brute had miscalculated the distance or its footing had given away, and the fall of such a heavy creature from the great height must have hurt it sorely. With one accord the two men pulled themselves to the edge and looked down. They were just in time to see what they had at first mistaken for a stone rise to its feet, give one snarl of rage, and then spring upon the mass that had fallen from above and was thrashing about helplessly on the ground. As it shot through the air, white teeth, like long daggers, glistened in the sides of the wide-open mouth. There was no mistake. They were face to face with the sabre-toothed tigers. [Illustration: An instant later a huge, dark form catapulted past the crouching men] Screams and snarls, hoarse bellowings and roars cut short by gurgling blood filled the air, mingled with the sound of the heavy, struggling bodies. The brutes were in a deadly embrace, and rolled over and over on the rock-strewn ground, biting, clawing, and tearing at one another with all the ferocity of their savage nature. The onlookers could not tell whether this was the settling of an ancient grudge, or if the tiger that had been on the ground had quickly realized the helplessness of the one that had fallen from above, and had taken advantage of the opportunity to easily rid the crater of one of its own kind, of which there may have been more than the limited space could conveniently support.