Purnell looked over towards the desk in the corner. The trusty had dropped a set of cards and was trying to pick them up. His hands shook so violently that in three trials he succeeded in getting only two cards back on the desk. His face was pale and the sound of his breathing rasped through the room. The warden looked over towards the man. "I'm sorry, Jim, I forgot it was your tour of duty. You can leave now." Jim hastily went through the side door of the room. Purnell turned back towards the warden's desk. Rol and Dorta, for Greg decided that these must be their names, were not men, though almost human. Their faces had two eyes, a nose and a mouth, but no ears. Purnell had seen natives of many different planets and knew how difficult it was to try to interpret the meaning of an alien expression. But he was certain that Rol and Dorta had absolutely no expressions on their faces. The two mertha walked on all fours and had heads which were more carnivorous looking than the men. They did not have any ears, either. Their appearance would not have disturbed Purnell, except for the memory of his sensations when they had bounded into the room. The men and the animals were clustered about the squat machine and each one wore a headset from it. The machine was buzzing softly. The buzzing stopped and Rol and Dorta took off all of the headsets. Warden Hughes spoke aloud to them, Purnell supposed out of courtesy to him, although the Zirthans are telepaths. "Now you know the thought-pattern of the escaped prisoner. The weather over the valley has turned bad, too bad for the helicopter. There are two zerda ready below. Cross the Malu by the lower bridge and cast along down the river. He will probably have turned off through the forest. If he doesn't try to hide there, he will head over the ridge towards Zadda City. He mustn't reach it." The two Zirthans saluted and silently left the room, followed by the mertha. The warden shrugged his shoulders and spoke to Purnell. "It's up to them, now. I apologize for exposing you to the mertha without warning. But I know that men in your job have healthy hearts. You got a touch of what is in store for that poor devil who got away." "What are the mertha?" asked Purnell. "Animals from Zirth," answered the warden. "They have the same telepathic sense that the men from Zirth have, but can detect thought-patterns many miles away, whereas a Zirthan must be near. Of course they are not very intelligent but they obey simple telepathed orders from the Zirthans." "But what happened when they came into the room? It was a terrifying feeling." Purnell shivered involuntarily as he spoke of it. The warden smiled grimly. "Yes, I've experienced it. You see, on Zirth the animals have no sense of hearing but instead can sense things telepathically. The mertha came into the room and sensed a stranger. They were 'barking' and 'growling' at you, but mentally. As soon as Dorta came in he called them off with a mental command."