Presumably these pieces were written by and for professional singers and musicians. They probably represent recital items; it is known from other sources that musicians in the Roman period regularly performed selections from Euripides and other poets, set to music of their own.
The musical notation takes the form of letters of the alphabet and other supplementary symbols written above the syllables of the poetic text, each one signifying a particular note. Groups of two or three notes that belong to the same syllable are linked together by a tie-line below and/or a double point (:) following. Longer time-values may be indicated by lines above the notes, but in general the rhythm is given by the metre of the verse. The interpretation of the note-symbols is known from a treatise on music by Alypius (fourth century AD?).
The Oxyrhynchus Papyri vol.LXV 4463