One of many female monsters in Greek mythology. She was daughter of Phorcys and Ceto (this is the probable interpretation of Hesiod, Theog. 295: see West's comm.), was half-woman, half-snake, and was mother by Typhon of several of the monsters killed by Heracles and others. The name may also be generic: Herodotus (9. 4) traces the descent of the Scythians to the union of an echidna (‘serpent’) with Heracles.