"This must have been the crater of an active volcano at one time," said the doctor in a low tone, as if influenced by the solitude of the spot. "I think we'll find I am right about the outlet of the stream." At length we reached the bottom of the vast cavity, and in the unaccustomed twilight caused by the foliage and the overhanging rocks (though it was still broad daylight) we could see a large pool of dark water, and, surrounding this lakelet, were a number of posts, each about six feet in height, and most of them were surmounted by a grinning skull, while a fetid atmosphere hung over the place like a pall. I felt the colour leave my face at the horror of the sight, and, glancing at the doctor, I noticed that his jaw was firmly set and his eyebrows knitted in grim determination. Yadillah, though used to scenes of cruelty in his younger days, turned an ashy grey, and I heard him mutter a sentence in which the word "Allah" caught my ear. "What does it mean?" I whispered. "They are the skulls of men killed in tribal fights, to take the mildest view of the situation," replied Dr. Conolly. "But I should not be surprised if this is the scene of gruesome practices of cannibalism." "Come on, let's get away from this horrible place," I exclaimed. "One moment," he replied, and, picking up a piece of stone, he threw it into the pool, which, although it obviously was fed by the stream, was absolutely unruffled on its surface. The ripples caused by the stone had barely reached the edge of the pond when a loathsome head appeared above the water and a pair of lidless eyes stared malignantly at us. Then, with an eel-like motion, the monster began to swim towards the spot where we were standing. It was a gigantic water-snake. "Ugh, you brute!" shouted the doctor, and, regardless of the consequences, he drew his Webley revolver and sent a .441-in. bullet crashing through the monster's head. With a quick motion the reptile turned and disappeared beneath the surface, discolouring the dark water with its blood; but hardly had the echoes of the report died away when the surrounding brushwood seemed alive with men, who, uttering furious cries, made directly for us. The surprise was complete, for before the doctor could raise his weapon or the rest of us lift a hand in self-defence we were borne to the ground and bound hand and foot with ropes of coco-fibre. The next few moments seemed like a dream. I was dimly conscious of the horde of yelling, savages, who danced around and over our prostrate bodies with every attitude of demoniac fury. Three of their number, evidently priests, judging by their fantastic garb and the bizarre markings of red and white paint that concealed their faces, stood by the edge of the pool solemnly calling upon their outraged deity; but whether the brute was dead or only wounded I could not ascertain, for their efforts were in vain.