Here's a mystery for all you liturgical sleuths. Why does the Missal of Paul VI contain the Entrance and Communion antiphons but not the Offertory antiphon? (The 1962 and earlier versions of the Roman Missal include all three for each Mass.) I searched in vain for an answer in Archbishop Bugnini's The Reform of the Liturgy (1948-1975) and elsewhere. According to the current General Instruction of the Roman Missal (with adaptations for the dioceses in the United States), "the norms on the manner of singing [the Offertory chant] are the same as for the Entrance chant" (no. 74). The norms regarding the Entrance chant are given in no. 48 ¶2: "If there is no singing at the entrance, the antiphon in the Missal is recited either by the faithful, or by some of them, or by a lector; otherwise, it is recited by the priest himself...." I take this to mean that if there is no singing at the Offertory (either the proper chant as given in the Roman Gradual, or a "suitable hymn"), then the antiphon in the Missal is to be recited. But that's precisely my point: there is no Offertory antiphon in the novus ordo Missal; how, then, can it be recited in the absence of singing? Am I missing something? I can live without an answer, but any help would be appreciated.
