The history of Serapis is on a large scale what that of the other sacred animals of Egypt is on a smaller scale. Mnevis was a lesser Apis; as Heliopolis waned before Memphis, so did its divine bull before the rival deity of the capital. They had both started on an equal footing, and had followed the fortunes of the cities where they were adored. At Mendes it was not a bull, but a ram, that was the object of worship, and in which the priests beheld an incarnation of Ra,(76) though the accidental fact that the word _ba_ meant alike "ram" and "soul" caused later generations to identify it with the "soul" of Osiris. In the Fayyûm it was the crocodile which naturally became the god Sebek or Sukhos, and at a later time Pete-sukhos, "the gift of Sukhos." In the latter name we read the signs of a growing disinclination to see in the animal the god himself or even his soul or double; the Sukhos becomes "the gift of Sukhos," separate from the god, and bestowed by him upon man.
There were other nomes besides the Fayyûm in which the crocodile was worshipped. It was the sacred animal of Onuphis in the Delta, and of Ombos in the far south of Egypt. But we must not expect to find a Sebek and a sacred crocodile always accompanying one another. There could be cases in which the crocodile was identified with other gods than Sebek,--with Set, for example, as at Nubti, near Dendera. The sacred animal existed before the god whose incarnation he afterwards became. The neolithic races were in the valley of the Nile before the Pharaonic Egyptians, and the deities they adored were consequently also there before the gods of the intruding race. Ptah, with his human figure, would not have been transformed into the bull Apis if the bull had not been already in possession.
The name of the god Thoth is itself a proof of this. Thoth was the god of Hermopolis, the modern Eshmunên, and his patronage of writing and books shows that he must have been the deity of the Pharaonic race. The god to whom the invention of the hieroglyphs was ascribed, could not have been the god of an illiterate population.
Now the Egyptian form of the name Thoth is Dehuti (or Zehuti), "he who belongs to the ibis."(77) Thoth, therefore, was not originally the ibis, and, in spite of his bird's head, the human body which he retained was a traditional evidence of the fact. He was merely "attached to the ibis,"--attached, that is to say, to the place where the ibis was the fetish of the aborigines.