"Fire!" cried Frank, when the others had their heavy magazine weapons ready.
A volley of lead poured into the ranks of the monsters and several of them, with horribly human shrieks, fled wounded toward the lake. A strong sickening odor of musk filled the air as the creatures bled.
But far from alarming the rest of the monsters the attack seemed to render them ten times more savage than before. With roars of rage they advanced toward the boys, making wonderful speed on their legs and flippers.
"Let 'em have it again," shouted Frank as he noted with anxiety that the first fusillade had been a failure, the rough coats and thick hide of the monsters deflecting the bullets.
Once more the adventurers emptied their pistols, but the shaggy coats of the great creatures still seemed to prevent the bullets doing any serious injury.
The boys' position was ominous indeed. An order from Frank to reload resulted in the discovery that he alone of any of the party had a belt full of cartridges; the others had all used up the few they had carried.
"We're goners sure," gasped Billy as the creatures hesitated before another scattering discharge of bullets, but still advanced, despite the fact that this time two were killed. Suddenly, however, their leader with a strange cry threw his head upward and seemed to sniff at the air as if in apprehension.
At the same instant a slight trembling of the ground on which the adventurers stood was perceptible.
"It's an earthquake," cried Billy, recollecting his experience in
Nicaragua.
With wild cries the monsters all plunged into the lake. They seemed to be in terror. Behind them they left several of their wounded, the latter making pitiful efforts to reach the water.