As others have noted, it is the Hawthorne & Sheble hanger for a cylinder machine horn. But don't despair - - there are known instances of manufacturers supplying cylinder machine horns as original equipment on disc machines. The Englewood Musicalphone used such an arrangement as seen on page 135 of the
Talking Machine Compendium. And there was definitely an arrangement between Hawthorne & Sheble and Zonophone as evidenced by the H&S "Silk Finish" horn with a Zonophone marking (on a characteristic H&S paper label) as seen on page 165 of the same book.
Your horn is a late H&S model (U.S. Patent No.38,478) and may very well be the original equipment on the Zonophone.
George P.