Searching in the internet, I find nothing referring to "Illix Aind".
In shotgunworld.com's forum, they say it could be "Felix Arnd Berlin," but again I do not find references.
The other inscription is "FURSTENWALDE Am / Spree."
Furstenwalde is still a town in eastern Germany located on the Spree river
About proofmarks, I found the meaning on (http://www.gunaccessory.com/Proof_Ma...oofmarks.htm#5
Thanks a lot for the help....