§ 50. In most houses, as in the Augustinian abbey of canons at Haughmond and of canonesses at Lacock, the chapter-house roof was on a level with that of the cloister, to allow of the continuation of the dorter or of a passage from the dorter to the transept across its western end. But in the larger houses, especially of the Benedictines, it was often an aisleless hall occupying the whole height of the range. Where, as at Canterbury, Gloucester and Reading, it was of this type and opened directly from the cloister, the dorter was obviously shut off from direct communication with the church. But at Bristol, Chester, Westminster and elsewhere, the lofty chapter-houses stood entirely at the back of the eastern range, and the dorter was carried across a vaulted vestibule, which was divided by columns into three or, at Westminster, into two alleys, and was either open to the cloister, as at Bristol, or, as at Chester, was entered by a doorway with a window on either side, like the doorway of the chapter-house beyond. It has been said that the chapter-house was usually planned without aisles: this was the case in the larger Benedictine houses, and in such houses of moderate size as Haughmond, the Premonstratensian abbey of Dryburgh in Scotland, or the Benedictine nunnery of St Radegund at Cambridge. But the Cistercian order preferred chapter-houses divided into alleys by rows of columns, and the influence of their beautiful buildings may be seen in the aisled chapter-houses of Lacock or of the Premonstratensian abbey of Beeleigh. Nor was the chapter-house always oblong. Apsidal examples have been given; and, when that at Gloucester was rebuilt in the fifteenth century, it was finished with a three-sided apse. There are also circular and polygonal chapter-houses. At Worcester the twelfth-century chapter-house is a circular building, entered directly from the cloister, and vaulted from a central column. In the fifteenth century, when the abutments shewed signs of giving way, it was remodelled externally into a ten-sided polygon. No vestibule was necessary here, as the dorter was placed in another part of the cloister, and more room could accordingly be given to the chapter-house. At Dore, the chapter-house was polygonal; at Margam it was internally circular, externally twelve-sided. The Benedictine chapter-house at Evesham was ten-sided. Between 1245 and 1250 was built the octagonal chapter-house of Westminster, the prototype of the secular buildings at Salisbury and Wells, raised upon an undercroft and divided from the cloister by a long vestibule; and there was another octagonal chapter-house in the Augustinian priory of Carlisle. The most peculiar plan was that of the twelfth-century Premonstratensian chapter-house at Alnwick, where a rectangular western vestibule was combined with a circular eastern portion of the same height, roofed in one span without a central column.