The Liturgy of St. Gregory is similar to the ancient Roman liturgy. The differences with what would be known as the "Extraordinary Form" would be the absence of the
Filioque, an explicit descending
epiclesis, and the fact that the Extraordinary Form is based on the 1962 Missal. (The Liturgy of St. Gregory predates '62 and hence the '62 Missal.) Other minor differences would be the translation of the word "merits," and the substitution of the Patriarch of Antioch for the Pope.
The Liturgy of St. Tikhon differs a great deal from the 1928 Book of Common Prayer, as it is greatly augmented. It is more like an Anglican Missal Mass, corrected for Orthodox theology. While he was hierarch in North America, a number of Episcopalians approached St. Tikhon (Bellavin) to join the Orthodox Church and use something akin to their BCP; he petitioned the Holy Synod of Russia. The Synod issued a number of changes but left their implementation to the bishop on the ground. All changes they recommended to the Mass and Hours were implemented by the Antiochian Archdiocese when they adopted this liturgy. (The Hours for this, Morning and Evening Prayer, are found in The English Office.) Augmentations would include the
Asperges (often prayed before Mass), Prayers at the Foot of the Altar, Introit, Gradual/Tract, Alleluia/Sequence, lack of
Filioque, Offertory verse, Offertory Prayers, a stronger descending
epiclesis, Communion verse, Post-Communion prayers,
Agnus Dei,
Domine Non Sum Dignus, invocations of the prayers of the Mother of God and other saints, a prayer for the dead, the Embolism on the Lord's Prayer, and the return of the
Gloria to its traditional position following the
Kyrie (off the top of my head). The Patriarch of Antioch asked the Byzantine pre-communion prayers to be recited in this liturgy.
Here's a post on the topic [
westernorthodox.blogspot.com].
I hope that helps.
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Western Orthodoxy Blog [westernorthodox.blogspot.com]
