Ἀλλ' Ἀχέροντι νυμφεύσω → I will become the bride of Acheron
θύρηθι, Ion. and Ep. for θύρα, θύραθι.
θύρη: θύρηθε, Ἰων. καὶ Ἐπ. ἀντὶ θύρα, θύραθεν.