As regards the entrenchment and stockading of the camp, the task falls upon the allies concerning those two sides along which their two wings are quartered, the other two sides being assigned to the Romans, one to each legion.
Each side having been divided into sections, one for each maniple, the centurions stand by and superintend the details, while two of the tribunes exercise a general supervision over the work on each side;
and it is these latter officers who superintend all other work connected with the camp. They divide themselves into pairs, and each pair is on duty in turn for two months out of six, supervising all field operations.
The prefects of the allies divide their duties on the same system.
Every day at dawn the cavalry officers and centurions attend at the tents of the tribunes, and the tribunes proceed to that of the consul.
He gives the necessary orders to the tribunes, and they pass them on to the cavalry officers and centurions, who convey them to the soldiers when the proper time comes.
The way in which they secure the passing round of the watchword for the night is as follows:
from the tenth maniple of each class of infantry and cavalry, the maniple which is encamped at the lower end of the street, a man is chosen who is relieved from guard duty, and he attends every day at sunset at the tent of the tribune, and receiving from him the watchword — that is a wooden tablet with the word inscribed on it — takes his leave, and on returning to his quarters passes on the watchword and tablet before witnesses to the commander of the next maniple, who in turn passes it to the one next him. All do the same until it reaches the first maniples, those encamped near the tents of the tribunes. These latter are obliged to deliver the tablet to the tribunes before dark.
So that if all those issued are returned, the tribune knows that the watchword has been given to all the maniples, and has passed through all on its way back to him.
If any one of them is missing, he makes inquiry at once, as he knows by the marks from what quarter the tablet has not returned, and whoever is responsible for the stoppage meets with the punishment he merits.
Walbank Commentary