CALLIRRHOE, in Greek legend, second daughter of the river-god Achelous and wife of Alcmaeon (q.v.). On his death, she prayed that her two young sons might grow to manhood at once and avenge their father. This prayer was granted; and her sons, Amphoterus and Acarnan, slew Phegeus, the murderer of Alcmaeon, and returning with the necklace and robe (peplos) of Harmonic (q.v.; see also ALCMAEON), dedicated them at Delphi (Ovid, Metam. ix. 413) .