Ref. Mark Kinsler's request for Symphonion information [180420
MMDigest].  Some pictures of the box and a disc would most helpful.
The 13+" size points to the American branch of Symphonion, the
Imperial Symphonion.  I can give you lots more information once
I see the pictures!

Nancy Fratti - Nancy Fratti Music Boxes
Canastota, New York
http://www.nancyfrattimusicboxes.com/