"Let's go, Kewpie Doll," snapped Venard. "And don't try to guess why. Although in your case, I can't see the danger." "Goodbye," said La Crue as a Guard appeared to lead them through secret tunnels to their waiting Scouter. "And good luck...." IV There are no adventures in space. Either a space-flight is safe monotony, or quick death. But as the two Guardsmen approached the vast mysterious dome of S.S.C. somewhere in the Mesozoic nightmare, the vaporous, steaming, endlessly stretching rain-forest of Venus, they stumbled with wracking weariness. Reptile-infested swamps and steaming seas, foul-smelling, rotten--it was an incredibly perilous planet. For five hours they had burned their way through giant flora and fauna and sweat, H-guns hot with almost steady usage. And then Venard finally parted some phosphorescent, glowing lichen and there the gigantic dome rose up and up and lost itself in thick mist. But between them and their goal was a hellish nightmare barrier, spilling stinking muck into a placidly steaming sea. Larson mopped at mud and sweat-slimed face, stared in fearful awe. Venard swore. They were blocked by a moat, a green, oozing mud-river, flowing oilily. From out of it, projected huge spines, ribs, and warts covering towering, brilliant, multi-colored mounds--that _moved_! Scaly mountains of shifting, radioactive lime. "Giant mollusc bed!" gasped Venard. Low tide now, but during high tide the sea on their right would back up this far. But high tide was hours distant. There were thousands of the molluscs, every size, shape and color. Venard's head went quickly to either side. "It goes out of sight both ways, Kewpie Doll. Into the sea and into the swamp. Trapped!" Larson squirmed, muttering, "Them bivalves are flesh-eaters. Look!" A _gruoon_, a flying reptile, had started a dive across the thick air toward the fungus-covered dome of S.S.C. A giant bivalve, at least fifty meters wide, snapped open. Its lifting shell-half dripped an avalanche of tendrils and muddy slime. A pliable snout whipped upwards. On its end, a formless pliant mouth full of row after row of rasp-like teeth, closed on the _gruoon_, sucked it into the pallid grey pulsating interior of the bivalve. Its shells closed with slow certainty on the writhing, screaming _gruoon_. "We can't make that trek on foot, Kewpie Doll. Got to get back to the ship. We landed on the wrong side. Got to rush things though, and get the Zharkon's brain before the Marties try illegal entry and ruin everything. Come on. I'll get you inside S.S.C., don't worry." "I'll worry either way--hey, listen!" He froze. His eyes rolled up and followed the sound droning invisibly above the impenetrable envelope of mist--the long _hissshowwww_ of a decelerating Martian war-ship.