The peril which menaced the explorers was more frightful than any that they had been called upon to face since entering that mysterious land known by the name of the Matto Grosso.

The Aryks numbered more than half a hundred, all active, vigilant and armed with their fearful poisoned javelins. They had taken position among the trees on the western bank of the Xingu, at the base of the rapids, at the very point where the white men intended to shoulder their canoe and make their last portage.

Instead of being in the open, where they were in plain sight of the defenders, and fair targets for their unerring Winchesters, they were stationed behind the numerous trunks or lying on the ground, where little could be seen of them except their bushy heads and gleaming black eyes, as they glared with inextinguishable hate at the white men who had slain so many of their number.

The suspicious Long was looking in the direction, with the thought that if any ambush was attempted, that would be the very spot, when he caught sight of a dusky figure, as it whisked from behind a narrow trunk to another that afforded better cover.

That hasty glance in the dim morning light revealed an alarming number of heads glaring around the trees and from among the undergrowth like so many wild beasts, aflame with fury and the exultation of savages who knew that their enemies were at last forced inextricably into their grasp.

So assured were the Aryks in fact that they showed a disposition to toy for a moment with their victims, as a cat does with a mouse before craunching it in her jaws. They brandished their weapons, danced grotesquely and uttered shrill shrieks audible above the deafening roar of the angry Xingu as it foamed through the rapids.

It was a fearful trap in which our friends found themselves, for it was impossible to advance or retreat, and it was madness to hope that they could again escape the shower of spears that were already poised in the air and ready to be launched.

Bippo and Pedros, with wild shrieks of terror bounded into the canoe, and wrapping the blankets around them, cowered in abject helpless dread of impending death. They were only an incumbrance, as they had proven in more than one crisis before.

But not one of the Caucasians showed the white feather. Disdaining to seek impossible shelter, they coolly prepared to die fighting, while exposed to the hurtling javelins, whose appalling effectiveness they knew too well.

But at this appalling juncture, when life hung on the passing moment, a piercing shout rang out above the roar of the waters.

It came from a point behind them, and, despite the imminent peril all three looked around.

A small canoe was darting across the Xingu toward them, so close to the foot of the rapids, that it danced about like a cork and seemed certain to be submerged every minute.

In this frail craft sat the giant Ziffak, propelling it across the furious swirl with such prodigious power that though the spume dashed over it, the boat was driven by the sheer power of his mighty arms under, above, and through the waters.

It was he who uttered the resounding cry which caused the wondering explorers to turn their heads, and stayed the uplifted arms of the venomous Aryks.

All saw the giant head chieftain of the Murhapas who repeated the shout and added an exclamation that was a command, forbidding his allies to hurl a single weapon.

They must have deemed him mad, but if so he was ten times more to be dreaded than if sane. Not a javelin was launched, but all stood motionless awaiting his arrival, and doubtless believing he meant them to pause only long enough to place himself at their head as the leader.

They must have thought, too, that his appearance so filled the whites with fear that their arms were paralyzed, for, though he was in direct range, not a hand of the foreigners was raised to do him hurt.

Coming with such tremendous speed, Ziffak occupied but a moment in passing the remaining distance. Before the prow of his boat could touch land, he flung the paddle aside, spurned the canoe with his foot, caught up his huge spear, and with one bound placed himse............