Steckel fell back instantly. With Mortenson beside him he followed the trail, the others strung out on either side. Slowly they went on for what seemed hours. It was hard work for them to go through the lush. It was as tough and fibrous as dried coconut husks. Had it not been for their heavy clothing they would have been cut to shreds in no time. Their hands suffered from the ordeal, but it could not be helped. They had not prepared for such conditions and it was too late to go back. They were at last on the trail of the phantom killer. Only death or inconceivable terror could drive them from it. The man must be apprehended at any cost and each had secretly resolved to see the thing through to a finish. Yet they derived a certain sense of pride from the fact that they were among the first humans ever to tread this strange, blue-tinted world. Police history would long remember them for their daring. Suddenly there was a violent commotion in the lush not far ahead. Abruptly the intrepid man-hunters halted in their tracks. Machine guns were snapped forward. Then a terrifying shriek rent the stillness. Mortenson's blood chilled and he crouched instinctively. The others did likewise from natural instinct, weapons aimed straight ahead to sweep the wall of vegetation with a deadly fire. For a moment thereafter the place was as silent as a tomb. Then another shriek came from ahead. Tensely the men waited and then the thing appeared, head and shoulders above the swaying, rolling sea of lush. Barton let out a feverish yell and snapped up his gun. It rattled with a staccato snap. The men stood erect to see an incredible monstrosity staring at them through a triangle of eyes that seemed to spit blue flame. The monster of the Fifth Dimension was like an awful nightmare. It had a long, reptilian neck, at the end of which was a venomous-looking head. Its eyes, as large as saucers, were deep set in the forehead, like the three corners of a triangle. From its neck spurted streams of greenish-blue liquid, spilling through the wounds made by Barton's missiles. The enormous head was studded with unnumbered horns and waved back and forth, a long, purple tongue darting from between fang-filled jaws. With a sudden lunge the beast moved toward the men. "Shoot!" Steckel bellowed, aghast. "Don't stand there like a squad of statues! Shoot!" The machine guns went into action with an ominous deadliness. The first barrage literally clipped the monster's head from its body. The beast leaped high in the air and fell with a thud, to writhe in the throes of agony and death. Its long, reptilian tail lashed out, beating madly. Finally the creature lay still and the men went cautiously toward it. The beast had the legs of a centipede, but thick and powerful. The feet were four-toed and savagely clawed. Mortenson was astounded to find a cross between the reptile and the insect and he promptly named it a _serpenta insecteana_.