Waywardangler, after pondering what you have there, even though I have never seen anything like them before now, ..... back when I was a kid and an avid fisherman for bass, suckers, catfish, etc., ......... they look like something that I would have liked to have had.
Me thinks them babies would have been "just the berries" for making "doughballs" for suckers and catfish fishing.
Just mix up a concoction of flour, water, etc., ...... then fill those thingys up with it ....... by pinching it open and then by either using a heaping spoon full or sticking it down into the mixture, ...... then let it close up ...... and then drop it in boiling water.
And "bingo", when you take it out of the water n' open it up ..... ya got a perfectly shaped "doughball" ready to put on a hook.
That sure would beat using a spoon to "drop" a lump of uncooked dough into the boiling water.
Oh, and ps about catfishing. My Pappy told me how best to catch a lot of catfish in a river. First ya get a burlap sack, then ya put a gallon or so of something really smelly (he suggested chicken guts) into it, then a pretty good sized rock and then tie the end tightly shut. Then ya toss it into some shoal water (where the river narrows and runs faster) and then come back in 3 or 4 days or a week .... and fish in the deeper water right below the shoals.
He said those catfish will come from a 1/2 mile down river to feed on "whatsa smelling good" to them.
cheers