Its sides had been raised to permit the free flow of air, and he could see the creatures plucking food from strange vessels and goblets with their snakey tentacles. All about the tents green men and copper-skinned hunters milled in a senseless jostling confusion like a circus breaking its stand. Suddenly, his eyes narrowed. The octopods were being waited on by a hairless pink-skinned species of human. That made four distinct races he'd observed since landing. He ticked them off on his fingers--the cave people, the red-haired fighting men, the green and stolid porters. Now these bald, hairless white slugs of men. The white men were doing most of the work, herding the porters about, packing chop boxes. Jupiter frowned. An odd little protuberance, he discovered, sprouted from the backs of all their necks. The protuberances varied in size, some no larger than a small snail shell, others as big as a tangerine. They were plum-colored and looked as if they were made of horn. What the devil could the things be? He shifted his eyes to a lank, coppery fighting man and saw that he bore one of the things on the back of his neck also. They all did, he realized with a sudden dryness of mouth. All along he'd been aware vaguely of the stiffness in his spine. With a thrill of alarm, he felt the back of his neck, touched a knob-like thing just below the base of his skull. The shock of the discovery left him sick at his stomach. He examined it gently with his finger tips. It was small, hard. He had the uncomfortable conviction that it was alive, feeding off of him like a leech. He tugged at it, but it was firmly anchored, the flesh about it quite numb. In panic he tried to twist it off. Instantly a blinding flash of pain seared through him like acid tingling out to the very tips of his fingers. He pitched forward, cracked his head on the bars of his cage, slid to a prone position. For moments he lay there unable to lift a finger although his brain was clear, lucid. It was as if the thing had perceived his intention and had paralyzed the voluntary motor centers of his brain! * * * * * With mounting horror, Jones realized that the mollusk-like organism must be fastened directly to his spinal cord. He had best not meddle with it again until he learned more about it. "_Za'min--car?_" he heard a voice say behind him. He sat up, looked around, realized with a start that the paralysis was gone, leaving no appreciable ill effects. There was a girl in the next cage watching him out of wide yellow eyes. She was one of the cave people, he recognized with a scowl of suspicion. It was impossible to mistake the air of wildness about her--like a caged leopard. She was quite naked, crouching in her cell with her uncombed black hair hanging down to her sturdy brown shoulders. "Za'min--car?" she repeated. He shook his head. What the devil was the girl driving at? She looked puzzled then touched her breast, said: "Lete." "Lady?"