k, k. Smaller trap-door for lifts, (for dogs?).

B. Brick Arches of Nero supporting the Tufa Wall and Arch.

n, n, n. Level of the original pavement.

o. Passage.

p. Ancient tufa wall.

q. Brick arch of Nero, under an arch of tufa.

r. Segment of another brick arch of Nero, abutting against the centre of the tufa arch to support it, like an arch-buttress or flying-buttress of the Middle Ages. (For the Phototype of this arch, see Plate [IX.])

s. Socket for a pivot to work in.

THE COLOSSEUM.
PLATE XVI.

SUBSTRUCTURES EXCAVATED IN 1875,
With probable Restorations of the Lifts or Pegmata.