The seats of the ima cavea and media cavea were reached through a vaulted passage (4), which, in accordance with ancient usage, we may call a crypt. It ran under the first seats of the second range, and stairs led from it to both divisions. It might be entered either from the two broad corridors leading to the arena, or directly from the west side by means of two separate passages (_c_, _d_, on the plan). It is, however, interrupted at the middle on each side of the Amphitheatre. On the west side the prolongation of the crypt would have interfered with the use of the corridor leading to the Death Gate; but as no such reason existed for blocking the east branch, it is probable that the designers of the Amphitheatre interrupted both branches of the crypt in order to force the spectators who had seats in the lower and middle divisions of the south half of the structure to enter and leave by the somewhat inconvenient south entrances, which are situated in an angle of the city wall. Had the crypt been carried completely around, the crowd would always have pressed into the building through the north entrances, which opened toward the city, thus causing confusion, if not danger, on occasions of special interest. [Illustration: PLATE VI.--INTERIOR OF THE AMPHITHEATRE, LOOKING NORTHWEST] In the corridor leading from the north entrance, as may be seen on the plan, a row of stones with square holes in them were placed in the pavement near the left wall. In these stakes could be set and connected by ropes, thus making a narrow passageway along the side. The purpose of the arrangement is not difficult to understand. Through the north corridor the gladiators entered and left the building, and the wild beasts were brought in; so provision had to be made to give them a passage separate from that used by the spectators. Before the commencement of an exhibition the whole entrance was accessible to the populace, which eagerly crowded forward to secure seats in good season. When they had for the most part found their places, the barrier was set up, and only a narrow alley was left along the east wall for belated spectators who wished to pass into the crypt on that side; the rest of the passage was reserved for the gladiators, and the spectators whose seats were reached from the opposite branches of the crypt were obliged to use the side entrance (_c_). [Illustration: Fig. 99.--Transverse section of the Amphitheatre.]