eanwhile the other allosaurus remained crouched, whining impatiently for its keepers to cast it loose.
Fixing burning eyes upon the American, the foremost keeper threw back his head. "Ahre-e-e!" he shouted. Instantly the freed allosaurus arose, balanced its enormous bulk, then commenced to leap forward at tremendous speed, clearing fifteen or twenty feet with each jump and uttering a curious, whistling scream as it bore down, a terrifying vision of gleaming teeth and talons.
Shaking off the paralysis of despair, Nelson whipped up the Winchester and, as before, sighted squarely between those blazing, gemlike eyes. When the huge monster was but twenty feet away he fired, and the report thundered and banged in the cavern like the crash of a summer storm. In mid-air the ghastly carnivore teemed to stagger. Its tail twitched sharply as in an effort to recover its balance. Then, quite like any normal creature that is shot through the head, it lost all sense of direction and made great convulsive leaps, around and around, clawing madly at the air, bumping into the rock walls and uttering soul-shaking shrieks of agony. Like a gargoyle gone mad it reeled back towards the startled rank of spearmen. As it came, Nelson saw the second allosaurus rear itself backwards and, balanced on its tail, strike out with powerful hind legs as its maddened fellow drew near.
Like razors the great talons ripped through the dying allosaurus' belly, exposing the gray-red intestines as the stricken creature raced by, snapping crazily at the empty air.
A single mighty sweep of the monster's tail crushed five or six of the panic-stricken keepers and guards, strewing them like broken and abandoned marionettes among the stones. Hissing and obviously terrified, the second dinosaur watched the dying struggles of its mate; then, obedient to a terrified shout from its keepers, wheeled about to join in a frantic rout of the spearmen, who, casting aside shield, spear and brass coil, fled for dear life in the direction of those invisible passages through which they had appeared.
CHAPTER II
o less amazed and alarmed than those vanished soldiers, Nelson remained rooted to the ground, conscious that in the swallow's nest overhead there remained only the officer—a tall, broad shouldered man with golden beard showing from under the cheek pieces of his helmet. Across the body of the still writhing monster their glances met. Nelson could see by the light of those strange pillars of fire that the other's eyes were blue as any Norseman's. Leaning far out over the stone parapet the other stared down upon the aviator from the depths of his jewelled helmet in a strange mixture of curiosity and awe.
Suddenly Nelson's nerves snapped and he shook a trembling fist at the martial figure above.