Where the bass part appears to move between B flat and E natural, the Es should be read as E flats. - Mick Swithinbank
This is a spelling mistake! The motet "O sacrum conuium" don't exists, the right name is: "O sacrum convivium"; "ui" is the ancient term for "vi" --> "Con-ui-ui-um" (and not "con-ui-um") must be write "convivium"! Please correct the error in Voice (I am not able to do this).