Santa Maria del Carmine e Sant'Antonio was a small mid 19th century devotional chapel in what was the Via Pedacchia, most of which is now under the Via del Teatro di Marcello to the west of Il Vittoriano near Piazza Venezia. This is in the rione Campitelli.
The Via Pedacchia was a mediaeval street which started from the south-east corner of the Piazza di San Marco, then ran south, south-west and west to the former piazza with fountain which is now in the Via di San Venanzio. It was destroyed in the building of Il Vittoriano in the late 1880's.
The site is under the western wing of that monument.
This was described as a small but very well decorated chapel. It had a beautiful altar with a large picture of Our Lady of Mount Carmel, and a smaller one below of SS Anthony and Philomena.
It does not appear on the Nolli map, and the devotion to St Philomena indicates a date of foundation in the mid19th century.