The earthmaking process may, among the less advanced races, be begun by a bird, or some other animal (whence the term " theriomorphism "), for the high idea of a god is impossible, till man has fully realized his own humanity.
Again the Homeric Zeus is fully anthropomorphic; but in many domains of Greek religion we discover the traces of theriomorphism, when the deity was regarded as often incarnate in the form of an animal or the animal might itself be worshipped in its own right.
We may indeed with Mr Andrew Lang explain the many myths of the bestial transformations of Zeus on the theory that the God was the tribal ancestor and assumed the shape of the animal-totem in order to engender the tribal patriarch; 7 but on the actual cults of Zeus theriomorphism has left less trace than on those.