[Illustration: IMPRESSION OF A CYLINDER-SEAL ENGRAVED WITH A SCENE REPRESENTING GILGAMESH AND EA-BANI IN CONFLICT WITH BULLS IN A WOODED AND MOUNTAINOUS COUNTRY.--_Brit. Mus., No._ 89308.] [Illustration: IMPRESSION OF A CYLINDER-SEAL ENGRAVED WITH A SCENE REPRESENTING MYTHOLOGICAL BEINGS, BULLS, AND LIONS IN CONFLICT.--_Brit. Mus., No._ 89538.] In the same category with the monsters on the vase we may class the human-headed bulls, of which small sculptured figures, in a recumbent attitude, have been found at Tello; these were afterwards adopted by the Assyrian kings, and employed as the colossal guardians of their palace door-ways. The extent to which this particular form of composite monster was employed for religious and decorative purposes may be seen on the cylinder-seals, upon which in the earlier period it represents the favourite device. Examples are frequently found in decorative combinations, together with figures of early bearded heroes, possibly to be identified with Gilgamesh, and with a strange creature, half-man and half-bull, resembling the later descriptions of Ea-bani, who strive with lions and other animals.[44] Gudea's catalogue of the temple furniture and votive objects, with which he enriched E-ninnû, throws light upon the manner in which Sumerian art reflected this aspect of the Sumerian religion. Some of the legends and beliefs may well have been derived from Semitic sources, but the imagery, which exerted so strong an influence upon the development of their art, may probably be traced to the Sumerians themselves. The engraving upon cylinder-seals during the Sumerian period appears to have been done generally by hand, without the help of a drill or a revolving tool.[45] Outline engraving with the point was also practised, that on stone having probably preceded the use of the bas-relief,[46] but it continued to be employed in the later periods for the decoration of metal and shell. The finest example of metal engraving is the silver vase of Entemena, around which is incised in outline a decorative band, consisting of variations of the emblem of Lagash, arranged beneath a row of seven calves. But the largest number of designs engraved in outline have been found, not upon stone or metal, but upon shell. It is an interesting fact that among the smaller objects found by M. de Sarzec at Tello, there is not a single fragment of ivory, and it would seem that this material was not known to the earliest inhabitants of Babylonia, a fact which has some bearing on the disputed question of their relations to Egypt, and to the earlier stages of Egyptian culture.[47]