This isn't a strictly musical question, but I noticed that the appendix to the Roman Missal that contains the tones for the readings, the introduction differs from what is in the lectionary and commonly heard at Mass. As an example, the Missal has "A reading from the first letter of the blessed Apostle Paul to the Corinthians," while the Lectionary would have "A reading from the first letter of Saint Paul to the Corinthians." My hunch is that the discrepancy is due to the Missal being in its third edition and the Lectionary not having been revised in a while. If that is the case, would it be proper to always use the Missal introduction, despite what is printed in the Lectionary, or should the Missal introduction be reserved for introducing chanted readings only?
I would use what is in the Lectionary for both read and sung instances - the missal is of course translating the Latin literally, but (a) it is a sample meant to illustrate the tone, not text (b) there are variations between the national Lectionaries on introductions, and if the missal wished to make it uniform, it would have been clearly indicated e.g. in the Ordinary, as is the case for "The Word of the Lord". (c) there are certain inaccuracies e.g. even the Latin Lectionary no longer speaks of St. Paul as the author of the Letter to the Hebrews.
I can see using the missal appendix as a legitimate justification for the sung readings, but my opinion would be to use the Lectionary.
To participate in the discussions on Catholic church music, sign in or register as a forum member, The forum is a project of the Church Music Association of America.