"I'm sorry. All the Earth broadcasts that we intercepted gave me a working knowledge of the _spoken_ word, sir, but I'm afraid their actual word symbols are beyond me. It would take trained linguists months, perhaps years, to get a correlation between the sound of the word and its written image." "Drog?" said Gwann, turning to the navigator. Drog took the rotting sheet in his hands and studied the configurations of the continents. After a bit, he brightened. "Sir, I think I can figure this out. According to our landing calculations, we are here." He jabbed a digit at one section of the page, and was distressed when it went right through. "The material seems to be falling apart, sir." "Perhaps," Jorik suggested, "it is undergoing some unnatural stress--possibly tied up somehow with whatever it was that depopulated this city?" "A good point, Jorik," said Gwann. * * * * * A long black shadow slid across the pavement near their feet and the five Venusians, very much startled, looked overhead. They were barely in time to see the huge gray form of the carnivore before it vanished behind a sign atop a nearby building which bore the mystifying information "Pepsi-Cola." "There, sir!" cried Jorik. "That's exactly like the one I saw earlier!" "Those _teeth_!" Klendro whimpered. "They could bite one of us in two!" "And what they could do to us, they could do to an Earthman," Gwann said speculatively. "From the sizes of the doorways in these buildings, and the clothing on display in the shop windows, the Earthmen could not have been much larger than us." "Sir," said Drog, holding up the map so that the leader could see it, "look here. This blue section that runs all over the map. You see, it's marked circle-arc-fork-cone-zigzag." "Yes," said Gwann. "I see. What about it?" "Well, sir, it recurs on the map, but each time it has a new group of symbols in front of it. What can it mean?" Gwann frowned and studied the five symbols: O-C-E-A-N. "Seems to suggest a similarity between all of them," said Jorik. "Perhaps the first symbol only means that the section is in a different place." All five Venusians studied A-R-C-T-I-C, A-N-T-A-R-C-T-I-C, I-N-D-I-A-N, and the other symbols that were used in conjunction with the mysterious O-C-E-A-N. "A tribal tabu!" exclaimed Jorik. "What are you talking about, Jorik?" said Gwann impatiently. "You recall I said there seemed something strange about the consolidation of the populace in certain areas? The wasted land space?" "Yes, yes. What about it?" "All these sections marked O-C-E-A-N are the unused areas. There must have been some sort of tribal superstition about dwelling in those areas. That would explain why all the people lived on the higher ground here." "I--I would have expected to find something _blue_ in that area," said Gwann uncertainly. "Or else why is it so marked?"