CHURCH OF S. AGNESE, founded by Constantine, on the site where the body of the saint was found. The aisles are formed by thirty-two columns of fine marble, and the altar canopy is supported by four columns of porphyry. In the second chapel on the right is a beautiful altar inlaid with mosaic work. Pio Nono's escape when the floor fell in, April 15, 1855, is commemorated by a fresco by Tojetti. The feast of the saint is on the 21st January, when the lambs are blessed with great ceremony. Here we have the best idea of a basilica. THE CATACOMB OF S. AGNESE. _Entrance in the church. Open on Sunday, Tuesday, and Thursday._ Part of this catacomb under the garden of the monks is well worth a visit. The entrance to it is through the church, and the exit through S. Costanza. The original stairs at the entrance were excavated in 1873, and four pagan tombs were found and two openings from them into the catacomb, showing that the Catacombs were general cemeteries, and not _exclusively_ Christian. This catacomb is interesting, as it is left just as it was found in 1871, many of the graves being unopened.--The neighbouring CHURCH OF S. COSTANZA was erected to the memory of Constantine's daughter, Constantina, who was anything but a saint according to Marcellinus. It is worth visiting on account of its dome, supported by twenty-four clustered columns in granite, and covered with mosaics. The sarcophagus is now in the Vatican Museum. S. Costanza is a mausoleum and a baptistery, not properly a church. The mosaic pictures of the fourth century are the finest known of that period. Those over the doors are of the eighth century. "At this time [A.D. 360] Julian sent the body of his wife Helen, recently deceased, to Rome, to be buried in the suburb on the road to Nomentum, where also Constantina, his sister-in-law, the wife of Gallus, had been buried" (Marcellinus, xxi. i. 5). _A quarter of a mile beyond the church, on the left, is the entrance to_ THE OSTORIAN CATACOMB. (_Custodian, Valentino._)