I believe I found the answer:
*Synopsis of the Pius XII Reforms
In the Holy Week reform of 1955, the following changes were made to the Mass of Palm Sunday. Items two and three also apply to Holy Tuesday and Spy Wednesday.
- In the reform of 1955, the three synoptic Passions were shortened at the beginning; the first 35 verses of Saint Matthew were removed, the first 31 verses of Saint Mark, and the first 38 of Saint Luke. Furthermore, at the end of the Passion of Saint Matthew, the last six verses were also removed. These passages appear nowhere else in the Roman Missal, which therefore no longer contains the Gospel account of the preparations which the Lord made for the celebration of the Last Supper, the washing and anointing of His feet, the betrayal of Judas, and the Last Supper itself. From the end of the Passion of Saint Matthew was removed the account of the guard set by Pilate and the Pharisees at the tomb of Jesus, a passage which has no parallel in the other Gospels.*