Cooperit Calicem, genuflectit, surgit, et inclinatus Sacramento, iunctis manibus, et ter pectus percutiens, intellegibili voce dicit:
The priest covers the chalice, genuflects and rises. Bowing before the Blessed Sacrament with joined hands, he says the Agnus Dei in an audible voice and strikes his breast three times — at each “miserére nobis” and at “dona nobis pacem”. At a sung Mass the choir takes it up.
priest:
In Missis Defunctorum non dicitur miserére nobis, sed eius loco dona eis requiem, et in tertio additur sempitérnam.
This rubric governs Masses for the dead: there “dona eis réquiem” takes the place of “miserére nobis”, and the third time “dona eis réquiem sempitérnam”. At those Masses the priest does not strike his breast, and the kiss of peace is not given.