Four half-men awkwardly holding hands inside four concentric bands.

[ChenZheChina]

You are right, those are Roman numerals: "Cap lxxxiiii" "Cap lxxxv" Chapter 84 and 85.

Thanks, Marco. I did not see the / of X as they were too thin  

The diagram below the wheel is unfinished: all text and labels in the diagram are missing, even if the layout was clearly planned to have them (compare with the Cava de' Tirreni manuscript). A first possibility is that this smaller wheel also was meant as a diagram whose labels were never added. Alternatively, the pointing gestures of the two standing people below the wheel could suggest that it represent the sun.

I see, so the wheel-like object might be an unfinished sun.