The edifice (Fig. 1232) consists of a choir and transepts. Of the nave hardly anything exists, and there is nothing to indicate that it ever was built. The present west wall is modern, probably of this century. The choir measures, internally, 13 feet from east to west by 18 feet 6 inches wide. The total length across the transepts is about 53 feet 6 inches from north to south by 13 feet in width, all inside dimensions. It will be observed that the nave and choir are not quite in the same line. The crossing (Fig. 1233) is covered with a pointed barrel vault in continuation of that of the choir, and is supported at the springing by very massive low round arches, which span the entrance to each transept. The choir vault is separated from the crossing by a late arch, supported on pillasters of a Renaissance form, and it has been emphasised by having ribs on the surface of the vault, as shown on the Plan by dotted lines, but these do not now exist. The transepts are also vaulted with plain pointed vaults carried to a considerable height, but cut off from the crossing, as at Ladykirk and Queensferry, by the arches introduced to carry the central vault of the crossing. As the church was without buttresses, the walls are of considerable thickness (not less than 4 feet) in order to resist the pressure of the arches. In the north wall of the south transept, near the apex of the roof (see Fig. 1233), there is a small door, now built up, which probably gave access to a small chamber in the haunch of the vault over the crossing. [Illustration: FIG. 1232.--St. Bothan’s Collegiate Church. Plan.] In the east wall of the north transept there is a piscina (Fig. 1234), enriched with carved crockets round the ogee arch. The basin is, as usual, broken away. On one side of the arch is a shield, having a smaller shield on the dexter side, bearing three inescutcheons, and on the sinister side three cinquefoils, being the arms of Hay of Tweeddale. The piscina is 22½ inches wide, measuring over the enrichments, by 26 inches high, and 3 feet 3 inches from the floor up to the level of the basin. [Illustration: FIG. 1233.--St. Bothan’s Collegiate Church. From South Transept.] [Illustration: FIG. 1234.--St. Bothan’s Collegiate Church. Piscina.] There is an end window in each of the three limbs of the cross, and none in the side walls. The windows in the transepts (Figs. 1235 and 1236), although not entirely alike in their details, have a general resemblance to each other. They are flat arched, and have mullions with a plain space above, occupying the centre of the thickness of the wall. The windows are of three lights, with circular tops fitted with cusping. The space above the lights, usually occupied [Illustration: FIG. 1235.--St. Bothan’s Collegiate Church. Transept Window (Exterior).]