Seeds, Beads, Pods, Shells? I'm stumped!

[dream*peddler]

This is a long endless strand of what I first thought was shells but now I don't think so.  They are very light and measure about 20mm by 10mm each.  I just don't have a clue as to what they are.  Thanks for any help!

[clearsphere]

They sure look like seed pods, but haven't seen such a unique pattern. Reminds me of tiger's eye a bit. Are they very fragile or sturdy? Are the beads in between the same material? Very interesting-I like them very much!

[old.crows.nest]

Not sure how helpful this might be but the round wheel-like beads kinda look like plastic coated fish vertebrae.

[dream*peddler]

Thanks for commenting, clear and OCN!  I posted on the bead board but no answer there.  My gut feeling is that they are some sort of pod that has been shellacked.  I feel like if I pinch one between by fingers it would break, but I'd have to use some pressure.  I think the spacers are the same material.  Hadn't thought about marine life, OCN.   I thank you both for having a look!