atque Ixionii vento rota constitit orbis: "and the circle of Ixion's wheel was halted by the wind" (R.D. Williams).
Ixionii"—(apparently) from Ixioneus, Ixionius, "belonging to Ixion." (What case?)
Orbis (rotation?): Nom. sg? Acc. pl. ? Gen. sg?
The scansion seems to make "rota" (wheel) either nom. or acc. sg.
Can anyone explain the grammar of this line to me?