The arched niche, either blind or pierced with doors or windows, is used at Ukhaiḍir to complete the decoration of the north wall of the great hall. Blind niches with a rectangular frame stand on either side of the central calotte, while above it the three niches are pierced by windows. Here and in all other examples at Ukhaiḍir, the opening, simulated or real, is covered by a shallow calotte. In the central court the single niche at the south-east corner is potentially a doorway; it is covered by a fluted semi-dome (compare the doubtful example at Mshattâ, above, p. 118). In the same manner the niches on the two side walls of room 32 are potentially windows; at Karkh, where they are similarly placed, but in outer walls, they are actually pierced by window openings. The single niche motive is found in room 140, where, however, the niche is unusually shallow. That the form of such niches as those of the great hall and of rooms 31 and 32 is Hellenistic is not open to a moment’s doubt. Out of the countless classical parallels I may cite the aedicula upon the east façade of the basilica at Shaqqah.[359] The archivolt at Shaqqah is carried on colonnettes, the semi-dome is fluted, and the addition of a pediment, in the true Graeco-Roman style of Syria, involves the doubling of the colonnettes. The purely decorative character of the aedicula may well be compared with that of the niches on either side of the central calotte in the great hall. Dr. Reuther draws an apt parallel between the placing of the niches in the great hall and the placing of the niches in the building on the citadel at ‘Ammân,[360] and he calls attention to the fact that at ‘Ammân the colonnettes have neither capital nor bases and that the archivolts of one of the pairs of niches in room 32 are decorated with a zigzag ornament analogous to that of ‘Ammân. All these points help to prove the Mohammadan origin of the building on the citadel. It is not, however, strictly correct to describe the colonnettes either at ‘Ammân or at Ukhaiḍir as being without capitals. They are all provided with a small impost block. In room 32 a strikingly oriental motive is introduced into the niches on the side walls. The spear-shaped ornament in the centre of each niche was familiar to Assyrian decoration. Whether it had, or had not, its origin in the spear-shaped loopholes of fortified walls,[361] it is used for purely ornamental purposes in Assyrian decorative crenellations at Assur and in Parthian crenellations at Warka.[362] It was common in a similar position during the Achaemenid period,[363] and was carried on into later Mohammadan work, with the difference that the whole niche was given a spear-shaped or trifoliate heading[364] (Plate 75, Fig. 1). Nor are the recessed rosettes of the stucco decoration at Ukhaiḍir connected with Hellenistic types; they have affinities with the rosette motives of Assyrian fresco and enamelled brick,[365] but the