Accent.—For special rule of accent in the genitive plural, see cross208. The genitive plural is always perispomenon since -ῶν is contracted from -έ-ων derived from original (and Hom.) -ά_-ων ( cross51). Final -αι is treated as short ( cross169).
a. The form of the gen. pl. is taken from the pronominal adjective, i.e. (Hom.) θεά_ων
Herbert Weir Smyth [n.d.], A Greek Grammar for Colleges; Machine readable text [info] [word count] [Smyth].