A luminous something was glowing outside the cabin. It searched and prodded about the deserted deck to whip upward at the audible hiss of wet carbide. Another appeared; the rifle came slowly to the man's shoulder as a pair of jaws gaped glowingly beyond the windows and an eye stared unblinkingly from its hornlike sheath. It crashed madly against the walls of the wireless room to shatter the glass and make kindling of the woodwork of the sash. Thorpe fired once and again before the specter vanished, and he knew with sickening certainty that the wounds were only messages to some central brain that would send other ravening tentacles against them. But the oak bars had held. He reached in the brief interval for the key, and he sent out one final call for help. He strained his ears against the head-set for some friendly human word of hope. "--rocket," the wireless man was saying. "Fire rockets. We can't find--" A swift, writhing arm wrapped crushingly about the cabin as the message ceased. * * * * * Thorpe seized his rifle and fired into the gray mass that bulged with terrible muscular contractions through the window. He fired again to aim lengthways of the arm and inflict as damaging a wound as his weapon would permit. The arm relaxed, but a score of others took up the attack. Again the sickening stench was about them as gaping jaws gleamed fiery beneath the hateful eyes and tore at the flimsy structure. Thorpe jammed more cartridges into the gun and fired again and again, then dropped the weapon to fumble for the rockets that Brent had given him. He lighted one with trembling fingers; the first ball shot straight into a waiting mouth. Another ignited a searing flame of acetlylene gas where a wet arm writhed in the hot carbide trail. The man leaned far out through the broken window. No time to look around. He let the red flares stream upward high into the air, then dropped the rocket hissing on the deck to seize once more the rifle. A mass of muscle crashed against the door; it went to splinters under the impact, and only the two oak bars remained to hold in check the horrible tentacles and the darting heads. One mouth closed to a pointed end that forced its way between the bars. The oak gave under the strain as Robert Thorpe pulled vainly at an empty gun. Beside him rose shrieks of terror as the monstrous thing came on, and Thorpe beat with frantic fury with his clubbed rifle at the fleshy snout. He knew as he swung the weapon that the shrieks had ceased, then smiled grimly in the numbing horror as he realized that Ruth Allaire was beside him. A piece of oak was in her hands, and she was striking with desperate and silent fury at the slimy flesh. * * * * *