Commentary Inf XIX 22-24

We shall later learn that Dante here comes face to feet with a pope, Nicholas III ([Inf XIX 69-72]). The inverted figure, like Judas in the central mouth of Lucifer ([Inf XXXIV 63]), has his head within, his legs without. Dante's use of bocca (mouth) for the opening of the hole into which he descends suggests that eventually Nicholas will be eaten and digested by hell itself once the next simoniac pope comes to his eternal station. For both these interpretations see Herzman and Stephany (Herz.1978.1), pp. 59, 65.