Another lantern of interest is to be seen in southern France in the cathedral of Notre Dame-des-Doms at Avignon (probably cir. middle of twelfth century).[318] Here the transepts are narrower than the nave and in order to make the crossing square, a series of four arches has been thrown across between the spandrels of the nave and choir arches, Over the square thus formed is an octagonal lantern on squinches which in turn supports a circular dome with the unusual feature of a series of flat pilaster-like ribs along its-under surface. Such ribs are, of course, largely decorative and correspond to those found in the apses of many neighboring churches.[319] True ribbed domes were also used as a means of covering the crossing,[320] and this is but natural in view of the fact that such domes were quite frequently employed over circular churches, as for example Saint Sepulchre at Cambridge, and the Templar’s Chapel at Laon (Fig. 55),[321] while half domes of similar character appear over many apses of the Transitional period.[322] [Illustration: FIG. 55.--LAON, CHURCH OF THE TEMPLARS.] LOBED DOMES Similar domes to that just described at Avignon are quite common in Spain, where for that matter the lantern itself had a very remarkable development. Thus in the cathedral of Zamora (consecrated 1144) there is a dome with sixteen ribs. It is not of perfectly simple type, however, for the masonry between the ribs is curved slightly outward, giving it the form of a lobed dome.[323] The lobes are comparatively small, but otherwise not unlike such larger ones as those in SS. Sergius and Bacchus at Constantinople (cir. 527) and the Serapeum of the Villa Adriana at Tivoli (125-135). As far as construction is concerned this arrangement made it possible to lay up the masonry between the ribs with little or no centering, so that once the ribs were in place, the task of completing the dome was a comparatively simple one. Unlike the “Gothic dome” which is later discussed, the thrusts were not materially decreased by the lobed plan and in its essentials the dome thus formed was precisely like the simple type. From the point of view of appearance these Spanish lanterns are certainly very beautiful. Usually pierced with windows in twelve out of the sixteen bays, and sometimes, as at Salamanca, with a few windows in the lower of the two stages forming the drum, they admit a great quantity of light to the very heart of the church where its presence is most needed. Moreover, the spherical pendentives from which the lanterns rise are more pleasing than the squinches generally found in France. “GOTHIC DOMES” OR DOUBLE CHEVETS