The remains at Hatra are further remarkable for a considerable number of reservoirs and tombs.  The open space between the town proper and the eastern wall and gate is dotted with edifices of a square shape, standing apart from one another, which are reasonably regarded as sepulchres.  These are built in a solid way, of hewn stone, and consist either of one or two chambers.  They vary in size from twenty feet square to forty, and are generally of about the same height.  Some are perfectly plain, but the exteriors of others are ornamented with pilasters.  The reservoirs occur in the paved court which surrounds the main building; they have narrow apertures, but expand below the aperture into the shape of a bell, and are carefully constructed of well-cut stones closely fitted together.

The material used at Hatra is uniformly a brownish gray limestone; and the cutting is so clean and smooth that it is doubted whether the stones have needed any cement.  If cement has been employed, at any rate it cannot now be seen, the stones everywhere appearing to touch one another.

There are several buildings remaining in Persia, the date of which cannot be much later than that of the Hatra edifice; but, as it is on the whole more probable that they belong to the Sassanian than to the Parthian period, no account of them will be given here.  It will be sufficient to observe that their architecture grows naturally out of that which was in use at Hatra, and that thus we are entitled to ascribe to Parthian times and to subjects of the Parthian Empire that impulse to Oriental architecture which awoke it to renewed life after a sleep of ages, and which in a short time produced such imposing results as the Takht-i-Khuzroo at Ctesiphon, the ruins of Shapur, and the triumphal arch at Takht-i-Bostan.

The decorative and fictile art of the Parthians has received no inconsiderable amount of illustration from remains discovered, in the years 1850-1852, in Babylonia.  In combination with a series of Parthian coins were found by Mr. Loftus, on the site of the ancient Erech (now Warka), a number of objects in clay, plaster, and metal, enabling us to form a fair idea of the mode in which purely Parthian edifices were decorated during the best times of the empire, and of the style that then prevailed in respect of personal ornaments, domestic utensils, and other objects capable, more or less, of aesthetic handling.  The remains discovered comprised numerous architectural fragments in plaster and brick; a large number of ornamental coffins; several statuettes in terra-cotta; jars, jugs, vases, and lamps in earthenware; some small glass bottles; and various personal decorations, such as beads, rings, and earrings.