τετράπνους
From LSJ
Δελφῖνα νήχεσθαι διδάσκεις: ἐπὶ τῶν ἐν ἐκείνοις τινὰ παιδοτριβούντων, ἐν οἷς ἤσκηται → Teaching dolphins to swim: is applied to those who are teaching something among people who are already well versed in it
German (Pape)
[Seite 1098] ουν, mit vier Nasenlöchern, Lycophr. 1313, auch im fem. τετράπνη.
