Unknown Pieces Made of Bone. Need Help!

These two pieces which seem to be made of animal bone came with a lot of Annam (Vietnamese) coins. They were brought back by an American soldier during the Vietnam War in the late 1960's.
Any idea what they might be?

I know that in Papua New Guinea, and surrounding areas the local tribes used to use bone or ceramic rings as currency. They were, as I remember, much larger than this- but they could be related.

Hope this helps:)

Citeer: "ShadowyEnigma"​I know that in Papua New Guinea, and surrounding areas the local tribes used to use bone or ceramic rings as currency. They were, as I remember, much larger than this- but they could be related.
​
​Hope this helps:)

​PNG? They could be made of human.

https://www.google.be/search?biw=1264&bih=653&tbm=isch&sa=1&ei=Ijx4WvTXHsrLwQKZgqvgCg&q=bone+money+papua&oq=bone+money+papua&gs_l=psy-ab.3...101538.104032.0.104953.5.5.0.0.0.0.64.305.5.5.0....0...1c.1.64.psy-ab..0.0.0....0._AZDAZQ5F-c

Citeer: "jlblonde"​

Citeer: "ShadowyEnigma"​I know that in Papua New Guinea, and surrounding areas the local tribes used to use bone or ceramic rings as currency. They were, as I remember, much larger than this- but they could be related.
​​
​​Hope this helps:)

​​PNG? They could be made of human.

...Hope not!