Passage 8.4.2
συνοικῆσαι δὲ οὐ θνητῇ γυναικὶ αὐτόν, ἀλλὰ νύμφῃ Δρυάδι ἔλεγον· Δρυάδας γὰρ δὴ καὶ Ἐπιμηλιάδας, τὰς δὲ αὐτῶν ἐκάλουν Ναΐδας, καὶ Ὁμήρῳ γε ἐν τοῖς ἔπεσι Ναΐδων νυμφῶν μάλιστά ἐστι μνήμη. τὴν δὲ νύμφην ταύτην καλοῦσιν Ἐρατώ, καὶ ἐκ ταύτης φασὶν Ἀρκάδι Ἀζᾶνα καὶ Ἀφείδαντα γενέσθαι καὶ Ἔλατον·
They said that he married not a mortal woman, but a Dryad nymph. For indeed there are Dryads and Epimeliads, and of these some were called Naiads; it is notably the Naiad nymphs whom Homer expressly mentions in his verses. This particular nymph they call Erato, and from her, they say, Arkas had three sons—Azan, Apheidas, and Elatus.