I think these are approximately 2 centimeters long, but am not actually certain. They are from Alabama, living in freshwater streams and rivers. They eat algae, diatoms, etc.. From what I've seen, they may only have been seen when they were dead. There does not appear to be any conservation measures in place for them. The problems they are facing is primarily pollutant run-off from forestry and the agricultural industry.
The animal itself is pretty much a guess on my part. I have seen pictures of the shells, but none of the actual gastropod. I looked at others from the same species and genus to come up with this representation. They are closely related to a couple other Elimia, though I don't personally think they are as pretty. I found it very interesting that they don't have an order they are assigned to. You probably remember the classification for everything goes: kingdom, phylum, class, order, family, genus, species. Well, these have: kingdom, phylum, class, whole lot of confusion, superfamily, family, genus, species. The poor thing dosn't know who its family is...well, it knows its family, but probably feels everything is out of order. Sorry, I found that funny as well as fascinating. I love genealogy, my grandpa did ours back to the dawn of time almost. I'm related to a whole host of fascinating characters. One of my relatives did graffiti in the Tower of London shortly before he was beheaded by Bloody Mary. He was Guilford Dudley, married to Lady Jane Grey who was queen for 9 days. If you go to the Tower of London, you can see where he carved "Jane" into the wall, it is under a bit of plexiglass.