In Greek mythology, the naiads ( Greek: ναϊάδες, naïádes) are a type of female spirit, or nymph, presiding over fountains, wells, springs, streams, brooks and other bodies of fresh water. They are distinct from river gods, who embodied rivers, and the very ancient spirits that inhabited the still waters of marshes, ponds and lagoon-lakes such as pre-Mycenaean Lerna in the Argolis. Naiads were often the object of archaic local cults, worshipped as essential to humans. Boys and girls at coming-of-age ceremonies dedicated their childish locks to the local naiad of the spring. In places like Lerna their waters' ritual cleansings were credited with magical medical properties.