The apostles can be identified by inscriptions on the dark band at their feet:
Left to right along the upper row: Matthias or Paul (inscription is illegible), Andrew (holding a cross in his left hand), John, Peter (keys), James the Greater (pilgrim's staff), Bartholomew (inscription lost, but note flaying knife).
Left to right along the lower row: Philip, Jude Thaddeus, Thomas, Matthew, Simon, and a young man not John who must be James the Less (Jacobus Minor).
More of the apostles as a group
This image in full resolution