The following is taken from Ritual Notes on the Order of Divine Service, Editors of "The Order of Divine Service," Oxford: Mowbray & Co., 1894. A great thrill to see the use of the word ‘Ceremonarius’ which is frankly quite delightful.
Naturally the following norms will suffice to cover all possible circumstances in which a Biretta is worn, and there will be no need for further debate or discussion. Oh no.
1. The Cross-bearer, Thurifer and Acolytes are allowed no head covering whatever and the Ceremonarius, even if he be in Holy Orders, may not under any circumstances, wear more than the zucchetto.
2. The Choir and Clergy may cover their heads outside the Church, but within the Church all must be uncovered, except the Officiant, Deacon and Sub-deacon (unless he be the Cross-bearer).
3. The Cantors in Copes may wear their birettas if in Holy Orders, but not otherwise.
4. All the other Clergy should carry their birettas, with both hands, below the breast.
5. When worn while sitting, the Biretta is always removed before standing.
6. The Biretta is not worn by the Sub-deacon when carrying the Cross.
7. If a priest on his way to celebrate a low Mass passes the High Altar, he makes, with head covered, a profound inclination to the Cross, or a genuflection, if the Blessed Sacrament be reserved in the Tabernacle.
8. If a priest on his way to celebrate a low Mass passes an Altar at which the Holy Eucharist is being celebrated: at the moment of the Consecration, he will kneel down on both knees, then uncover and adore, by an inclination of the head; he remains till the Consecration is ended, replaces his Biretta, rises and proceeds on his way. If he is not carrying the Chalice, he will remove his Biretta before kneeling, and not replace it until after he has risen from his knees.
9. A Biretta is not to be placed upon the Burse, when the priest is on his way to celebrate low Mass. Nor is his handkerchief or his spectacles He is not to place upon the Burse his handkerchief, or Biretta, or spectacles, or anything else for that matter.
10. Birettas should never be worn by the Celebrant and his Ministers between the foot of the Altar and the Sedilia.