Renou in his edition of Ptolemy's Indian books prints Εὐθυδημία. His note is: ‘Ἐὐθυδημία scripsimus: εὐθύδη X, εὐθημία Γ, εὐθυμηδία ω, -μέδια ἅ.’ His text is based on X (Vaticanus 191, thirteenth century) which all editors seem agreed is the best MS; Γ (Vatic. Palat. 388, fifteenth century) is said to exhibit some curious and erratic readings; ω is Renou's sign for the general body of MSS, and ἅ for the editio princeps of 1533 (Bâle) which Müller rated highly; it is based on Γ but has various divergences. The Latin versions all have -media. One MS of the group ω (Vat. Urbin. 82) is eleventh-century; -μηδία therefore is actually the oldest reading known, for what that may be worth.

It might be held that εὐθύδη of X warrants Εὐθυδημία, but Renou did not explicitly put it on that ground; there is little doubt from his note (scripsimus) that he adopted Bayer's old conjecture Εὐθυδημία because most writers since have done so. The historical considerations which make Εὐθυδημία impossible are dealt with in my text (pp. 247 sq.); here I am only considering Ptolemy's text.

The corruption of -μηδία into -δημία would be easy and obvious; Εὐθυδημία makes such good sense so long as one does not think about it, and the reasons which have affected the modern writer are precisely those which would have affected the ancient scribe.