I'm not sure either. Here's 109: St. Michael the Archangel, defend us in battle.  Be our protection against the wickedness and snares of the devil.  May God rebuke him, we humbly pray.  And do thou, Prince of the Heavenly Hosts,  by the power of God, cast down to Hell Satan and all his evil spirits,  who prowl about the world seeking the ruin of souls. Amen.