connected with a tube running north and south parallel with the vault of the corridor. The vaults are ovoid and are constructed of a single course of stones laid vertically supporting a mass of stone and concrete. In all the interior doors the arches are set back from the jambs (Plate 36, Fig. 1) and constructed in the manner described on p. 15. Upon the plaster of the west wall of No. 44, south of the door leading into No. 45, there is a graffito inscription in Arabic (see below, p. 161).[27] [Illustration: FIG. 4. South side of court B. (From _Ocheïdir_, by kind permission of Dr. Reuther.)] East of the lîwân group on the north side of court B there is a stair, and still further east a narrow passage within the outer wall. A small door in the north-east corner of the side chamber, 46, gives access to an unlighted blind passage under the stair. The stair runs up to a landing-place which is connected by a low doorway with a small chamber situated above the eastern passage. Another door leads into a gangway hollowed out of the thickness of the outer wall, and from this gangway a door leads into a tiny circular room in the outer towers. I did not determine whether the gangway in the wall runs on interruptedly from court to court. On the whole, as Dr. Reuther has observed, this would seem to be improbable since the strict isolation of the courts is in all other respects preserved. Almost exactly above the entrance to the stair (an awkward piece of construction) sprang the first arch of the arcade which flanked the court from north to south. In every court this arcade has fallen, but on the south side of court H a portion of the first arch remains, together with the vault behind it (Plate 35, Fig. 2). I cleared away the ruins at the south end of this arcade and found the remains of the first column at a distance of 2·40 metres from the south wall. The arcade must therefore have been composed of four columns carrying five arches, corresponding with the blind arcade on the opposite wall. The massive stone vaulting of Ukhaiḍir was not suited to free standing arcades, and, as has been noticed in the mosque, when the wooden cross-beams perished, their collapse was inevitable.