Based on an examination of the text of Priscian’s Institutiones Grammaticae in Sankt Gallen, Stiftsbibliothek, MS 904: 1. Corrections and additions to the text of the Old Irish glosses; 2. Some proposals about the translation or the interpretation of the St. Gall glosses; 3. An additional note on OIr. archiunn ‘a-head, further on’.