The vaulting of the presbytery (see Fig. 775) is peculiar, and points to a somewhat later time. It consists of a series of ribs spread over the surface of a pointed barrel vault, so as to form a definite pattern. These ribs produce a very rich effect, but they are a departure from the principles of true groined vaulting. This system was introduced in England at a late period, and led gradually to fan tracery. In the method of vaulting, adopted in late English work, the ribs are no longer relied on, as in genuine Gothic, as the strengthening nerves or centres which sustain the panels of the vault. They become mere ornaments on the surface of plain barrel or intersecting vaults, such as those used in Roman architecture. The vaults of late architecture in England (although ornamented with ribs) are thus constructed on the same principles as those of the pointed barrel vaults of late Scottish churches (of which numerous examples will be given hereafter), the only difference being that the latter are generally left plain, although occasionally enriched with ornamental surface ribs. Very fine examples of vaulting similar to that of the presbytery of Melrose may be seen at Winchester Cathedral[134] and other English examples of the fifteenth century. The south chapels to the west of the fifth buttress west from the transept, on which buttress another specimen of Abbot Hunter’s arms (Fig. 791) is engraved, are of comparatively late date. This buttress belongs to the earlier part of the nave, and the chapel seems to have been repaired when the additional chapels to the west were erected. Besides the three hunting horns in the shield of Abbot Hunter in the examples above mentioned, the arms engraved on the fifth buttress contain two crosiers saltierwise, and the initials A. H. on the right and left; also, in chief a rose, and in base a mason’s mell, for Melrose. The work in the chapels to the west is inferior to that of those to the eastward, although copied from them. The chapels each contain an enriched piscina (Fig. 792); and these are so inferior in style of workmanship as to lead to the belief that they were inserted after the chapels were built. One of them contains the initials of Abbot William Turnbull, whose date is the beginning of the sixteenth century. A late piscina (Fig. 793) has also been inserted in the south transept. [Illustration: FIG. 792.--Melrose Abbey. Piscina in South Chapel.] [Illustration: FIG. 793.--Melrose Abbey. Piscina in South Transept.] Work in the nave and in the south chapels was apparently in progress during the reign of James IV., as the royal arms (Fig. 794), with the letters I. Q. (Jacobus Quartus), and the date 1505 on the westmost buttress testify.