There was a rushing sound as of large bodies darting to and fro through the air; they heard the beat of powerful wings, low gasps and gurgles, yet could make out nothing in the obscurity. Then another terrible cry was heard—this time an unmistakably human one: ’Malto! Malto! Is it you? Save me! save me!’ This appeal startled their new friend into instant action, and he dashed toward the bars, crying out as he went, ’Have you arms, you three? If you have, come and help me!’ In a moment Gerald and Jack gripped their revolvers and raced after him. He made for a small metal gate in the bars, and after applying a key to the lock began feverishly to work away at other fastenings which still held it. The two chums stood beside him, gazing into the cage, trying to make out what was going on within. Suddenly something swished past them. It had the general appearance of a monstrous bat—certainly it had what looked like the body and wings of a bat—but it also had a human face! ’Malto! Malto!’ cried this apparition, as it flew past—for it was certainly flying—’make haste or it will be too late! I am tired out! I’—— The last words were lost as it disappeared again into the darkness beyond. Hardly had it passed when a huge shape came into view, beating the air with great wings, evidently in hot pursuit of the other. It was undoubtedly a monster bat—much bigger than the strange apparition with the human face. Without waiting for instructions from Malto, both the chums fired at the creature, but seemingly with no result; for it continued on its way, and a moment later was lost in the shadows. Malto looked up in surprise at the sound of the shots; then resumed his work at the fastenings, in which he was now assisted by Alondra. A moment later the gate was open. Malto snatched up a long, heavy piece of wood which was lying near, and, entering the cage, stood boldly waiting for the expected return of the monster. ’This way, Malandris! this way! The gate is open!’ he shouted, as he looked about, trying to pierce the gloom. There was a low answering cry, and the form of the man-bat—as he seemed to be—came into view, made a desperate attempt to keep up, but fell exhausted at Malto’s feet. Then the great bat itself appeared, and made a swoop to seize its prey. It was met with a blow from the heavy wooden bar, whereupon it turned viciously upon the rescuer. The great wings closed round him, and the immense claws with which they were armed gripped him, striving to draw him within reach of the head, with its open mouth and shining fangs. The wooden bar, however, was jammed against its breast, and prevented it for the moment from coming to close quarters. Just then Gerald and Jack, who had entered the cage behind Malto, fired their pistols simultaneously. As a result, one wing could be seen to be hanging limply, broken by a bullet; and as the creature gave utterance to another scream, Jack rushed in and despatched it.