As to the construction of the foss and vallum, two sides fall to the lot of the socii, each division taking that side along which it is quartered; the other two are left to the Romans, one to each legion. Each side is divided into portions according to the number of maniples, and the centurions stand by and superintend the work of each maniple; while two of the Tribunes superintend the construction of the whole side and see that it is adequate. In the same way the Tribunes superintend all other operations in the camp. They divide themselves in twos, and each pair is on duty for two months out of six; they draw lots for their turns, and the pair on whom the lot falls takes the superintendence of all active operations. The prefects of the socii divide their duty in the same way. At daybreak the officers of the cavalry and the centurions muster at the tents of the Tribunes, while the Tribunes go to that of the Consul. He gives the necessary orders to the Tribunes, they to the cavalry officers and centurions, and these last pass them on to the rank and file as occasion may demand. To secure the passing round of the watchword for the night the following course is followed. One man is selected from the tenth maniple, which, in the case both of cavalry and infantry, is quartered at the ends of the road between the tents; this man is relieved from guard-duty and appears each day about sunset at the tent of the Tribune on duty, takes the tessera or wooden tablet on which the watchword is inscribed, and returns to his own maniple and delivers the wooden tablet and watchword in the presence of witnesses to the chief officer of the maniple next his own; he in the same way to the officer of the next, and so on, until it arrives at the first maniple stationed next the Tribunes. These men are obliged to deliver the tablet ( tessera ) to the Tribunes before dark. If they are all handed in, the Tribune knows that the watchword has been delivered to all, and has passed through all the ranks back to his hands: but if any one is missing, he at once investigates the matter; for he knows by the marks on the tablets from which division of the army the tablet has not appeared; and the man who is discovered to be responsible for its non-appearance is visited with condign punishment.