(Κασταλίδες), the Castalian nymphs, by which the Muses are sometimes designated, as the Castalian spring was sacred to them. (Theocrit. 7.148; Martial, 7.11.)
[L.S]A Dictionary of Greek and Roman biography and mythology
Smith, William
A Dictionary of Greek and Roman biography and mythology. William Smith, LLD, ed. 1890