§354. The arena is shown in Fig. 158, its plan in Fig. 160. It was an ellipse with axes of 228 and 121 feet. Around it ran a wall a little more than six feet high, on a level with the top of which were the lowest seats. For the protection of the spectators when wild animals were shown, a grating of iron bars was put up on the top of the arena wall. Access to the arena and to the seats of the _cavea īma_ and the _cavea media_ was given by the two underground passageways, _1_ and _2_ in Fig. 160, of which _2_ turns at right angles on account of the city wall on the south. From the arena ran also a third passage, _5_, low and narrow, leading to the _porta Libitinēnsis_, through which the bodies of the dead were dragged with ropes and hooks. Near the mouths of these passages were small chambers or dens, marked _4_, _4_, _6_, the purposes of which are not known. The floor of the arena was covered with sand, as in the circus (§332), but in this case to soak up the blood as well as to give a firm footing to the gladiators. [Illustration: FIGURE 161. BISELLIUM] §355. Of the part of this amphitheater set aside for the spectators the _cavea īma_ only was supported upon artificial foundations. All the other seats were constructed in sections as means were obtained for the purpose, the people in the meantime finding places for themselves on the sloping banks as in the early theaters (§325). The _cavea īma_ was strictly not supplied with seats all the way around, a considerable section on the east and west sides being arranged with four low, broad ledges of stone, rising one above the other, on which the members of the city council could place the seats of honor (_bisellia_, Fig. 161) to which their rank entitled them. In the middle of the section on the east the lowest ledge is made of double width for some ten feet; this was the place set apart for the giver of the games and his friends. In the _cavea media_ and the _cavea summa_ the seats were of stone resting on the bank of earth. It is probable that all the places in the lowest section were reserved for people of distinction, that seats in the middle section were sold to the well-to-do, and that admission was free to the less desirable seats of the highest section. [Illustration: FIGURE 162. EXTERIOR OF THE COLISEUM]