is an officer appointed by the chapter of a cathedral, or in some cases by the dean alone, to act as the deputy of the latter. He is elected annually from the residentiaries, and sometimes by them. He acts as the locum- tenens of the dean, and is regarded as a paterfamilias. He usually sits in the north-west stall, although that is properly appropriated to the hebdomadary or canon in residence. In some Italian and Spanish foundations he is called prefect of the choir.