Gene turned curiously and took up a minute inspection of this tenth planet's terrain. Bleak and forbidding, jumbled masses of black rock stretch away to the horizon. Here and there, patches of slatish soil, naked and sterile, contended with the ever-present stone for surface space. He became aware of an insidious chill gnawing at his bones. Cautiously lifting the air helmet he had donned before emerging from the ship, he sniffed tentatively of the dry, thin air. It seemed to have no ill effects on him. He removed the helmet and stood irresolute, wondering what next to do. That problem was solved at once. Over the horizon came a howling, clamorous horde of man-shaped creatures, brandishing crudely fashioned spears tipped with sharpened stone, making straightway for the _New Frontiers_! Gene's hand went to his hip and came up bearing his energy-ray. Any question of the creatures' intentions was immediately dispelled as one of them jerked to a halt and flung his spear hard at the explorer. Gene ducked and came up blasting. A grim smile was on his lips as the rabble came on in spite of his withering fire, screeching like harpies as they closed in on him. He found time to wonder how the beings could see, for no eyes were evident on the flat, hateful faces. Wicked fangs gleamed in the gaping mouths; set squarely between where the eyes should have been was a diminutive, almost non-existent nose. Huge, batlike ears gave the finishing touch to their grotesque appearance. Gene felt a deep loathing for these weird denizens of a world that should not be. That abhorrence was reflected in the steady blast of his energy-ray, which cut a wide swath in the creatures' ranks. But still they advanced, shrieking and gnashing their teeth in black hate. They flung their spears with such clumsiness that Gene found them fairly easy to side-step, but now crude stone knives were brought into play, knives that were deadly, in spite of their unwieldiness. Once the beings gained close enough to use those weapons, the biologist would meet with a quick end. [Illustration: _Gene cut the half-men down one after another, but still they came on._] He fought silently, striving to work around the ship to the air lock, but the hideous half-men divined his purpose and swiftly moved to flank him, cutting off all escape. Gene cursed explosively and battled all the fiercer. Then he gaped in surprise as a spear whizzed past him and sank deep in the breast of his nearest attacker. A look of fear crossed the features of the ferocious barbarians, and as one they turned to face this new enemy. Gene, too, turned to look at the small band of sturdy beings advancing nimbly over the rocky ground, filling the air with well-aimed spears even as they came. His assailants made a show of standing firm under the onslaught, screeching defiantly and launching their spears haphazardly at the newcomers.