Er - I have no access to the site yet (Dark magic working against me, I think) so I couldn't check the spelling there; and I seem to be making my début on his list with a pedantic remark - but I think it is 'Priori IncantatEm' not '-tUm' (makes more sense in Latin, though I am aware that isn't a guarantee; in any case the Lexicon has -tEm).