earlier than Constantine, and perhaps later: the alterations and conversion into a church are not recorded; we only see the fact. Something was done in 1634, but I do not know what. Below this, in the valley, is the Grotto of the nymph Egeria, a cavern, perhaps originally formed by nature in the side of the hill, but enlarged and made regular by art, and the soft rock everywhere covered with brick, and reticulated work. It appears to have been formed into a symmetrical building adorned with niches; in one of which, at the end of the grotto, is a fragment of a male statue. The supply of water is but small, but the vault and walls, covered with the beautiful _Adiantum Capillus Veneris_, show the general moisture of the soil. Continuing down the valley, we meet with the Temple of Rediculus: the body of the work is of rubble, but it is faced with very neat brickwork, in which the horizontal surfaces of the bricks have been rubbed or cut away, in order to give room for the mortar, when the edges externally were almost in contact, as in the tomb called the sepulchre of Mars, and in some others near the mutatorium, which I have not particularly mentioned. I did not observe that any of the bricks were broken in consequence of this process, an effect which I think would certainly follow if a modern architect were to direct such a mode of proceeding. It has Corinthian pilasters at the back, which is the most conspicuous part, the foliage of whose capitals is also cut in brick. On one side are portions of two octagonal columns recessed in the wall, while the other side is plain. It has windows; and many of the ornaments round them, and in the cornice, and also a band, ornamented with a fret, which surrounds the edifice between the pilasters, seem to have been moulded in the clay, before being burnt. There are evident traces of a portico, towards the streamlet which waters the valley, so that the whole together must have formed a complete little prostyle temple. Within, the vault which separates the basement, from what would have been on such a supposition the floor of the temple, is broken away; and in this basement, on the west side, or end, is a row of small arches, which some antiquaries say are not parts of the building, but have been put up to support fodder for the cattle. As, however, traces of similar arches may be observed in the construction of the wall on the south side, whose surface is destroyed, I suspect that they were for the reception of cinerary urns. Whatever was the purpose of the erection, there are several buildings of a similar disposition about Rome, and therefore probably intended for a similar object. Most of them have been supposed to be temples, but I believe all contain appearances in the basement story, (for each has a basement story) of having been used as places of sepulture after burning: yet they are not placed immediately on the great roads, as sepulchres usually were, nor is there any certain