floret shape of the Assyrian rosette disappears with the perspective treatment. In a cruder form the rosette of Ukhaiḍir is used at Mâr Ṭahmâsgerd. Here it is not recessed but cut deeply into the wall, and its effect is produced solely by the resultant shadow. The crenellated motive of the stucco work in the mosque has its counterpart in the ornamental crenellations of Assyria and Persia, but it is used at Ukhaiḍir with singular freedom. The crenellations are combined so as to form recessed rhomboids; they are even applied to the archivolt in the two doorways of corridors 5 and 6.[366] Save for the rosettes, all the stucco decoration at Ukhaiḍir is of an architectural character--that is to say that it imitates plastic construction such as crenellations, arched and columned openings; or else it is an elaboration of structural details, such as the squinch or the transverse arch. Sometimes it is actually called into being by structural processes, as in the horizontal ridges of the vaults in the mosque and room 31. The motives placed on the summits of the vaults in rooms 31 and 32 are reminiscent of coffering, and I have little doubt that their origin is to be sought in the Hellenistic scheme of ceiling decoration. It is, however, interesting to note that Western forms are more obscured at Ukhaiḍir than in buildings of a later Mohammadan period. The stucco coffers of the vaults at Sâmarrâ stand very close to classical types,[367] whereas the coffers at Ukhaiḍir are employed in a manner foreign to classical conceptions. This must be largely due to the fact that in the great palaces at Sâmarrâ Western artificers were at work, while in the comparatively unimportant desert retreat oriental workmen and oriental ideas had the upper hand, yet I would suggest that the differences between Ukhaiḍir and Sâmarrâ indicate a considerable difference in date. In the ninth century Western influence was stronger in Mesopotamia than it was in the preceding age, when the arts were still held closely in the thrall of Sasanian tradition. Consequently we find at Sâmarrâ capitals inspired by the Corinthian acanthus capital, and among the wall decorations the Hellenistic vine motive plays a conspicuous part.[368] We have yet to learn that the flowing vine, so essential to Coptic decoration and to that of the Hellenistic coast-lands, was a feature of Sasanian architectural ornament. It occurs in monuments of the Umayyad period which were directly under the sway of Hellenistic Syria, such as Mshattâ and the miḥrâb of the Khâṣakî Djâmi’,[369] but except for sporadic examples in Parthian architecture, where the Hellenizing tendencies of the decorations are indisputable,[370] its systematic use on Babylonian soil begins (so far as the evidence goes) at Sâmarrâ in the middle of the ninth century, and there it was the artificers, not the work of their hands, which were imported. I do not deny that in comparison with the Sâmarrâ palaces Ukhaiḍir is a crude product of local