They resumed their march toward the distant invisible mountains, and were fortunate in finding somewhat better footing than they had on their previous march. They covered about 25 miles on that "day," without untoward incident. Their ray pistols gave them an insuperable advantage over the largest and most ferocious beasts they could expect to meet, so that they became more and more confident, despite the knowledge that they were rapidly using up the energy stored in their weapons. The first one had long ago been discarded, and the charge indicators of the other two were approaching zero at a disquieting rate. Forepaugh took them both, and from that time on he was careful never to waste a discharge except in case of a direct and unavoidable attack. This often entailed long waits or stealthy detours through sucking mud, and came near to ending both their lives. The Earth man was in the lead when it happened. Seeking an uncertain footing through a tangle of low-growing, thick, ghastly white vegetation, he placed a foot on what seemed to be a broad, flat rock projecting slightly above the ooze. Instantly there was a violent upheaval of mud; the seeming rock flew up like a trap-door, disclosing a cavernous mouth some seven feet across, and a thick, triangular tentacle flew up from its concealment in the mud in a vicious arc. Forepaugh leaped back barely in time to escape being swept in and engulfed. The end of the tentacle struck him a heavy blow on the chest, throwing him back with such force as to bowl Gunga over, and whirling the pistols out of his hands into a slimy, bulbous growth nearby, where they stuck in the phosphorescent cavities the force of their impact had made. * * * * * There was no time to recover the weapons. With a bellow of rage the beast was out of its bed and rushing at them. Nothing stayed its progress. Tough, heavily scaled trees thicker than a man's body shuddered and fell as its bulk brushed by them. But it was momentarily confused, and its first rush carried it past its dodging quarry. This momentary respite saved their lives. Rearing its plumed head to awesome heights, its knobby bark running with brown rivulets of water, a giant tree, even for that world of giants, offered refuge. The men scrambled up the rough trunk easily, finding plenty of hand and footholds. They came to rest on one of the shelflike circumvoluting rings, some twenty-five feet above the ground. Soon the blunt brown tentacles slithered in search of them, but failed to reach their refuge by inches. And now began the most terrible siege that interlopers in that primitive world can endure. From that cavernous, distended throat came a tremendous, world-shaking noise. "HOOM! HOOM! HOOM! HOOM! HOOM! HOOM!"