Ro moved cautiously. He knew the jungles of Mars well, knew the dangers, the swift death that could come to an unwary traveler. Many times he had seen fellow Martians die by the razor fangs of Gin, the swamp snake. Their clear red skin had become blotched and purple, their eyeballs popped, their faces swollen by the poison that raced through their veins. And Ro had seen the bones of luckless men vomited from the mouths of the Droo, the cannibal plants. And others there had been, some friends of