The corridor was accessible by four doors, one from the Forum Triangulare, another from the open space between this and the rounded exterior of the Theatre, a third at the end of an alley east of the temple of Isis, and a fourth opening from a steep passage leading up from Stabian Street. The summa cavea, which for convenience we may call the gallery, was entered by several doors (the exact number is uncertain) from a narrow vaulted passage along the outside. This passage, however, did not extend the whole length of the gallery, but stopped where the outer wall of the Theatre joined that of the Forum Triangulare. Here a stairway led to it; there was a second stairway at the rear of the Palaestra, and a third leading from the alley east of the temple of Isis; the three are shown on Plan III. At the edge of the Forum Triangulare, a narrow stairway, built in the thick wall, led directly to the gallery (Fig. 64). The outer wall back of the gallery rose to a considerable height above the last row of seats. On the inside near the top were projecting blocks of basalt (seen in Fig. 65), containing round holes in which strong wooden masts were set; from these the great awning, _velum_, was stretched over the cavea and orchestra to the roof of the stage, protecting the spectators from the sun. This sort of covering for the theatre was a Campanian invention, and here, where the cavea opened toward the south, was especially necessary. In the Coliseum, and the well preserved theatre at Orange, the arrangements for fastening the masts are on the outside of the wall. The upper part of the wall of our Theatre has been rebuilt in modern times, and it has been doubted whether the blocks of basalt and the pieces of cornice above with corresponding incisions are ancient; the latter surely are not modern, and their slightly wedged shape shows that from the beginning they must have been on the inside of the wall. Near the front of the orchestra at the right and the left were small rectangular platforms; one is shown in Fig. 65. They were supported by the vaults over the entrances (7, 7), and were reached by small stairways near the ends of the stage. They were called tribunals, and here, as in Rome, were no doubt reserved for the seats of those to whom special honor was paid. One was set aside for the use of the magistrate who gave the play; in Rome the vestal virgins, in accordance with a decree of Augustus, occupied the other, and in Pompeii their place was very likely taken by the city priestesses. [Illustration: Fig. 65.--View of the Large Theatre.] The shape of the orchestra is that of a semicircle enlarged in the direction of tangents at right angles with the diameter; a complete circle could be inscribed in the space. It was probably never used for a chorus, but was occupied by the seats of prominent spectators, particularly the city officials and their friends. It was entered by means of the vaulted passages under the tribunals.