2. A fabulous horse, which Poseidon begot by Demeter; for in order to escape from the
pursuit of Poseidon, the goddess had metamorphosed herself into a mare, and Poseidon deceived
her by assuming the figure of a horse. Demeter afterwards gave birth to the horse Arion, and a
daughter whose name remained unknown to the uninitiated. (Paus. l.c.) this
horse and Caerus were the offspring of Gaea; whereas, according to other traditions, Poseidon
or Zephyrus begot the horse by a Harpy. (ad Virg. Georg. 1.12.) From Poseidon the
horse passed through the hands of Copreus, Oncus, and Heracles, from whom it was received by
Adrastus. (Paus. l.c. ; Hesiod. Scut. Here. 120.)