Commentary Par XXXII 25-33

Dante once again insists on the absence of some saints-to-be in the Christian half of the Rose (the only place for which he specifies the eventual tenant is the throne destined for Henry VII [see the concluding verses of Par. XXX]).  He also refers to semicircles in order to alert us to the fact that there will be a matching descending line, one composed entirely of males, beneath John the Baptist.  To Mary's left and John's right sit the Hebrew saints; to her right and to his left, the Christian ones.  It is not stated, but seems clear, that we are to picture two different semicircles, with the midpoint of their arcs located at Mary and John, containing male saints (beneath Mary) and female saints (beneath John), except for the bisecting line, which is gendered as is each of them.  See the chart in C.Par.XXXII.37-39.