Anyone know what this with the Z is?

I have uploaded pictures of Belgique military medals from World War I. I pretty much figured out what all the medals were with the exception of two. The ones that have me baffled are silver metal with the Z just to the right of the photograph. The second medal I'm not sure about is the miniature silver medal in the center of the miniature ribbon bar directly underneath the photograph. Any information that you could provide would be greatly appreciated.