Cloacae (Lat. cloaca, a conduit, pipe), the sewers of ancient Rome. The trunk drain, called the cloaca maxima, is formed by three tiers of concentric arches overlying each other in contact; the whole work is 15 It. wide by 30 ft. in height. The masonry is of hewn stone, laid without cement. Along this subterranean street the drainage of the city, as well as the surplus waters of the aqueduct, discharged themselves into the river. The cleansing and repairing of the cloaca, were confided at first to the censors, afterward to the aediles, and subsequently to commissioners entitled curators of the cloaca?, who employed convicts in the work, and levied the expense by assessment. Tarquin the Elder is said to have originated these works about 150 years after the foundation of the city, for the purpose of draining the marshy ground between the Palatine and Capitoline hills. Agrippa sailed through the cloaca maxima in a boat. Nero caused his victims to be thrown into the sewers. The eloaeoo yet serve in part for the drainage of Rome, and several modern cities are drained similarly.