The upper view shews the exterior of the wall, with the three _specus_ passing through it, under an arch of the Claudian arcade, now destroyed. These are carried upon one of the piers of the Marcian arcade, built of squared stone, as the part near Rome always was. In the left lower corner of this view may be seen the Anio Vetus, half underground, as usual for this aqueduct. [This opening has been built up since the photograph was taken. The demolition of all traces of the old aqueduct as far as possible was part of the plan of the architect, who directed what were miscalled the _restorations_ of the City wall.] The lower view represents the _specus_ of the Aqua Marcia, of squared stone, carried on one of the arches of the Marcian arcade through the wall, within it at the same point as that of the exterior shewn above. PLATE XVI. CLAUDIA AND ANIO NOVUS. [Illustration: AQUEDUCTS ANIO NOVUS ON THE CAELIAN CLAUDIA AND ANIO NOVUS OVER THE PORTA MAGGIORE] I. OVER THE PORTA MAGGIORE. In the lower view the two _specus_ are seen endways, built of squared stone, as part of the gateway. The point of view for this is nearly the same as that of Plate XV., looking south instead of west. The curious tomb of the Baker Eurysaces is seen on the left, with the stone kneading-troughs of which it is built. II. The upper view is one corner of the great reservoir of Nero on the Cœlian, near the west end, over the Arch of Dolabella, which is seen built of well-cut stone, and perfectly plain. This has an inscription, with the names of the Consuls of the time of Augustus (A.D. 10), forty years afterwards; the arch, which was the eastern entrance into the Claudium, was used by the engineers of Nero as a substructure for the corner of the great reservoir of water for the supply of that part of Rome, which was carried at the height of thirty feet from the ground. Some small square windows are seen in the wall, which belonged to the chapel of S. Thomas _in formis_ (or in the arches), made in the remains of the arcade in the eighth century, and removed in the twelfth for a larger chapel, now in the garden of the Villa Celi-montana near to it. At the left-hand corner of this view is seen the gateway of the small monastery of the Redemptorists, with the celebrated mosaic picture over it, representing Christ between a black and a white slave, shewn in another plate of this work. PLATE XVII. ARCHES OF NERO WITHIN THE PORTA MAGGIORE. [Illustration: AQUEDUCTS. ARCHES OF NERO. WITHIN THE PORTA MAGGIORE. AQUA MARCIA, WITHIN THE PORTA MAGG: 1871.]