R for D before a Labial: Literary and Grammatical Evidence

On pg. 475–6 I mention some of the well known epigraphical examples of r for d before a labial, e.g. APVR FINEM (ILLRP 7, from the territory of the Marsi, end of the 4th century BCE), but I neglected to mention that there are also literary examples of the phenomenon and that it is commented upon by various ancient grammarians

The manuscripts of Cato's Agricultura give strong support to arvehant (138.1) and arvectum (135.7)

Priscian (Keil 2.35) wrote: antiquissimi uero pro ad frequentissime ar ponebant: aruenas, aruentores, |aruocatos, arfines, aruolare, arfari dicentes pro aduenas, aduentores, aduocatos, adfines, aduolare, adfari...

Marius Victorinus noted (Keil 6.9): Nos nunc et adventum et apud per d potius quam per r scribamus arventum et apur.

Velius Longus (Keil 7.71) quotes the forms arvorsus and arvorsarius.

Paulus ex Festo (p. 24 L) has apor glossed apud.

The so-called Glossary of Placidus (CGL 5.7.34 and 5.48.29) gives arveniet : adveniet.

Finally, the form arferia glossed by Paulus ex Festo (p. 10 L) as aqua, quae inferis libabatur, dicta a ferendo; sive vas vini quod sacris adhibebatur is almost certainly from *adferia. Cf. the Umbrian name for priest ařfertur, although in this last instance the form *ad- may not be identical to the adprep *ad.