Bk. IV. Ch. V. TOMBS. 345 The new form of toinb retained externally the circular form of tlio Pelaso-ic sepulchre, though consti-uctive necessities afterwards caused it to become polygonal. Instead, however, of being solid, or nearly so, the Avails M'ere only so thick as was necessary to support the dome, which became the universal form of roof of these buildings. The sepulchres of Rome have as yet been far too carelessly examined to enable us to trace all the steps by which the transformation took place, but as a general rule it may be stated that the gradual enlarge- ment of the central circular apartment is almost a certain test of the age of a tomb ; till at last, before the age of Constantine, they became in fact representations of the Pantlieon on a small scale, almost always with a crypt or circular vault below the principal apartment. One of the most curious transitional specimens is that found near San Vito, represented in Woodcut No. 225. Here as in all the earlier specimens, the principal apartment is the lower, in the square basement. The u])per, which has lost its decoration, has the appearance of having been hollowed out of the frustum of a gigantic Doric column, or rather out of a solid tower like the central one of the Tomb of xruns (Woodcut No. 176). Shortly after the age of this sepulchre the lower apartment became a mere crypt, and in such examples as those of the sepulchres of the Cornelia and Tossia families we have merely miniature Pantheons somewliat taller in ])roportion, and with a crypt. This is still more remarkable in a building called the Torre dei Schiavi, which has had a portico attached to one side, and in other respects looks very like a direct imitation of that celebrated temple. It seems certainly, however, to have been built for a tomb. Another tomb, very similar to that of the Tossia family, is called that of Sta. Helena, the mother of Constantine. If it is not hei's, it belongs at any rate to tlie last days of the Empire, and may be taken as a fair specimen of the tombs of that age and class. It is a vast transition from the tomb of Cecilia Metella,thougli,like all the changes introduced by the Romans, it shows the never-failing tendency to transfer all architectural embellishments from the exterior to the interior of every style of building. It consists of a basement about 100 ft. square, containing the cryi)t. 225. Section of ScinUchre at Sau A'ito. No scale.
