With reference to the question about a lay crucifer wearing a dalmatic, if he or she is not a deacon, the person is by definition wearing a tunicle. This is the vestment for the subdeacon at high mass ...

Subdeacon. The role of the subdeacon was split between the acolyte and the lector in the 1972 document from St. Paul VI. The subdeacon’s main liturgical charge was to chant the Epistle at Solemn ...