"The same desire for balanced composition determined the postures of the individual animals and humans in the frieze. The forms of the reversed animals in 53-55, 57, 58,... balance the outlines of the uprights heroes and rampant animals... Though the composite monsters of 57-59 may be mythological, it is possible that the merging of human and animal forms derived from a desire of the artist to maintian the essential symmetry and compactness of the composition as a whole... Frequently, as in 53, 55-57 ,the human heroes are joined in their fight by a bull-man, who makes his first appearance in this age. It was thought by earlier Assyriologists that this bull-man could be identified with Enkidu, the friend of the epic hero Gilgamesh, while Gilgamesh himself was identified with the nude bearded hero with curls." Porada, CANES, p. 9-10
Lion-headed eagle merged with reversed human, between two bull-men (in profile), one grasping reversed horned animal, which is menaced by lion that is in turn attacked by bull-man who initiates scene.