The Sumerians do not appear to have used complete shells for engraving, like those found on Assyrian and Aegean sites. A complete shell has indeed been recovered, but it is in an unworked state and bears a dedicatory formula of Ur-Ningirsu, the son and successor of Gudea. Since it is not a fine specimen of its class, we may suppose that it was selected for dedication merely as representing the finer shells employed by the workmen in the decoration of the temple-furniture. The Sumerians at a later period engraved designs upon mother-of-pearl. When used in plain pieces for inlaying it certainly gave a more brilliant effect than shell, but to the engraver it offered greater difficulties in consequence of its brittle and scaly surface. Pieces have been found, however, on which designs have been cut, and these were most frequently employed for enriching the handles of knives and daggers. The panels in the accompanying blocks will serve to show that the same traditional motives are reproduced which meet us in the earlier designs upon fragments of shell and cylinder-seals. They include a bearded hero, the eagle attacking the bull, a hero in conflict with a lion, the lion-headed eagle of Lagash, a winged lion, a lion attacking an ibex, and a stag. Even when allowance is made for the difficulties presented by the material, it will be seen that the designs themselves rank far below those found upon shell. The employment of mother-of-pearl for engraving may thus be assigned to a period of decadence in Sumerian art when it had lost much of its earlier freshness and vigour. [Illustration: Fig. 34.--Fig. 35.--Fig. 36.--Fig. 37. Four panels of mother-of pearl, engraved with Sumerian designs, which were employed for inlaying the handles of daggers. They belong to a period of decadence in Sumerian art.--In the Louvre; Cat. Nos. 232 ff.] The above brief sketch of the principal forms and productions of Sumerian art may serve to vindicate the claim of the Sumerians to a place among the more artistic races of antiquity. Much oriental art is merely quaint, or interesting from its history and peculiarities, but that of the Sumerians is considerably more than this. Its sculpture never acquired the dull monotony of the Assyrian bas-reliefs with their over-elaboration of detail, intended doubtless to cloak the poverty of the design. Certain conventions persisted through all periods, but the Sumerian sculptor was never a slave to them. He relied largely on his own taste and intelligence, and even the earliest work is bold and spirited. After centuries of independent development fresh vigour was introduced by the nomad Semitic races who settled in the north, but in the hands of the later Semites the Sumerian ideals were not maintained. For the finest period of Babylonian art we must go back to a time some centuries before the founding of the Babylonian monarchy.