It may be a Greener Ejector Model No. 1, a boxlock gun built with Greener-patent Self-acting Ejectors. These guns are often called G guns.
This is a Greener Ejector Model No. 1:
http://gunbroker.com/Auction/ViewItem.asp?Item=117518354According to the Greener book, Greener also made a grade of boxlocks called Monarchs. These guns were made with Anson & Deeley and Facile Princeps actions and all them had their ejector work in the forend (unlike Greeners with Self-Acting or Unique Ejectors).
From 1893-1903, Monarchs made on A & D actions came in 4 grades, Monarch G1 to Monarch G4.
Here's a Monarch built on the Facile Princeps action:
http://www.gunsamerica.com/976995339/Gun...rch_Grade_1.htmOWD