§336. A representation of a circus has been preserved to us in a board-game of some sort found at Bovillae (§329), which gives an excellent idea of the _spīna_, (Fig. 144). We know from various reliefs and mosaics that the _spīna_ of the Circus Maximus was covered with a series of statues and ornamental structures, such as obelisks, small temples or shrines, columns surmounted by statues, altars, trophies, and fountains. Augustus was the first to erect an obelisk in the Circus Maximus; it was restored in 1589 A.D., and now stands in the Piazza del Popolo, measuring without the base about 78 feet in height. Constantius erected another (Fig. 145) in the same circus, which now stands before the Lateran church, measuring 105 feet. The obelisk of the Circus of Maxentius now stands in the Piazza Navona. Besides these purely ornamental features, every circus had at each end of its _spīna_ a pedestal supporting seven large eggs (_ōva_) of marble, one of which was taken down at the end of each lap, in order that the people might know just how many remained to be run. Another and very different idea for the _spīna_ is shown in Fig. 146 from a mosaic at Lyons. This is a canal filled with water, with an obelisk in the middle. The _mētae_ in their developed form are shown very clearly in this mosaic, three conical pillars of stone set on a semicircular plinth, all of the most massive construction. §337. The Seats.--The seats around the arena in the Circus Maximus were originally of wood, but accidents owing to decay and losses by fire had led by the time of the Empire to reconstruction in marble except perhaps in the very highest rows. The seats in the other circuses seem to have been from the first of stone. At the foot of the tiers of seats was a marble platform (_podium_) which ran along both sides and the curved end, coextensive therefore with them. On this _podium_ were erected boxes for the use of the more important magistrates and officials of Rome, and here Augustus placed the seats of the senators and others of high rank. He also assigned seats throughout the whole _cavea_ to various classes and organizations, separating the women from the men, though up to his time they had sat together. Between the _podium_ and the track was a screen of open work, and when Caesar showed wild beasts in the circus he had a canal ten feet wide and ten feet deep dug next the _podium_ and filled with water as an additional protection. Access to the seats was given from the rear, numerous broad stairways running up to the _praecīnctiōnēs_ (§327), of which there were probably three in the Circus Maximus. The horizontal spaces between the _praecīnctiōnēs_ were called _maeniāna_, and each of these was in turn divided by stairways into _cuneī_ (§327), and the rows of seats in the _cuneī_ were called _gradūs_. The sittings in the row do not seem to have been marked off any more than they are now in the "bleachers" at our baseball grounds. When sittings