The church is cruciform, and the Plan (Fig. 763) has this peculiarity, that the choir is unusually short and the nave is unusually long. The choir extends, with aisles, only two bays eastwards from the crossing, beyond which point the presbytery is carried one bay further, without aisles, and is lighted by large windows on the north and south sides, as well as by the great eastern window. [Illustration: FIG. 764.--Melrose Abbey. Plan of Nave Pier.] The shortness of the choir rendered it necessary that part of the nave should be appropriated for the accommodation of the monks, and the enclosing screen wall of this portion of the “choir” extended to the fourth pier west from the crossing, where it was carried across the nave and formed the rood screen. This arrangement is apparent from the broken portions of the screen wall, which formed integral parts of the structure of the nave piers (Fig. 764), having been built along with them, thus showing that the screen constituted a feature in the original design. The part of this screen which crosses the nave still exists. It is wide, and contained a gallery, on top of which stood the rood. Fig. 765 shows the door through it from the nave. On the left is the small stone stair leading to the gallery. [Illustration: FIG. 765.--Melrose Abbey. Doorway in Rood Screen.] The nave now extends to eight bays in length, but it has been intended to be longer, the west end being incomplete; it is impossible, however, to say how far it was meant to extend. It is stated that the foundations of the nave have been found, in excavating, to reach to a considerable distance westward. The existing nave is 160 feet in length, and has north and south aisles. Extending southwards, beyond the south aisle, is a series of eight chapels, which produce, externally, along with the south aisle the appearance of a double aisle (Fig. 766). The north aisle is narrower than the south aisle, the former being 6 feet and the latter 11 feet in width. This difference may have arisen from the plan of the original abbey of the twelfth century being adhered to in the later reconstruction. The position of the cloister may have hampered the design, and prevented the north aisle from being widened in the direction of the cloister. The central nave is 26 feet in width, and the depth of the south chapels 13 feet 6 inches, and the total width of the nave, with aisles and chapels, is 68 feet. The transept consists of two portions--the north and south transepts--and contains the usual eastern aisle only, in which are situated four chapels. The total length of the transept over the crossing is 114 feet 6 inches, and the width of the north transept, including the aisle, is 40 feet 6 inches, while that of the south transept is 42 feet 6 inches.