For those who may not know, those type feeders were nick named (later) "Baby Killers" because they required rubber tubing which couldn't be cleaned properly and that retained toxic bacteria or ? that caused sickness or death.
I agree with the baby bottle. Looks like one end was closed when blown. Try browsing the Infant Feeders Collector's website, ACIF.ORG, there are several styles that are very similar to yours.
Thanks. I had no clue it was a specific catagory for collecting. It does look like some in the images. It's not bent though. It's flat like a pumpkin seed.
I'll email the club and see if they can verify and possibly identify it.