Θεογονία (320-340)

a creature fearful, great, swift footed and strong, who had three heads, one of a grim-eyed lion, another of a goat, and another of a snake, a fierce dragon; in her forepart she was a lion; in her hinderpart, a dragon; and in her middle, a goat, breathing forth a fearful blast of blazing fire.

Her did Pegasus and noble Bellerophon slay; but Echidna was subject in love to Orthus and brought forth the deadly Sphinx which destroyed the Cadmeans, and the Nemean lion, which Hera, the good wife of Zeus, brought up and made to haunt the hills of Nemea, a plague to men.

There he preyed upon the tribes of her own people and had power over Tretus of Nemea and Apesas: yet the strength of stout Heracles overcame him. And Ceto was joined in love to Phorcys and bore her youngest, the awful snake who guards

the apples all of gold in the secret places of the dark earth at its great bounds. This is the offspring of Ceto and Phorcys. And Tethys bore to Ocean eddying rivers, Nilus, and Alpheus, and deep-swirling Eridanus, Strymon, and Meander, and the fair stream of Ister,

and Phasis, and Rhesus, and the silver eddies of Achelous, Nessus, and Rhodius, Haliacmon, and Heptaporus, Granicus, and Aesepus, and holy Simois, and Peneus, and Hermus, and Caicus' fair stream, and great Sangarius, Ladon, Parthenius,