Holy Day of Obligation in the USA
Masses of the Dead, including burial Masses, are prohibited
Proper Mass; Gloria; Credo; commemoration of the feria; preface of the Blessed Virgin Mary Et te in Conceptione immaculata
Matins: Invitatorium Immaculatam Conceptionem; Hymn Praeclara custos; 3 Nocturns, all proper; Te Deum.
Lauds: Sunday psalms of the 1st scheme with the proper antiphons of the Feast; Hymn O gloriosa virginum; commemoration of the feria.
Prime: Ps 53 instead of Ps 117, verse Qui natus es, short lesson of Advent: Domine, miserere.
Hours: Sunday psalms with antiphons from Lauds.
II Vespers: Psalms from the Common with antiphons from Lauds; Hymn Ave, maris stella; commemoration of the feria.
Compline: Of Sunday