Upon further research, I don't think these are Physa at all. They don't really come to a point like the Physa I'm used to; they have an operculum, which Physa do not (according to applesnail.net); and they are incredible
algae eaters. Here's a before and after shot of an Anubias leaf:
So I did a little more looking around, and found this page
. Check the top right picture on the page, and see if you don't think this looks the same. In fact, the snail there even has the same kind of chip on the apex of the shell! So I think these are Olive Nerites, Vitta usnea
So the good news is I have some excellent algae eaters; the bad news is I wanted to breed these snails, and that sounds next to impossible. Plus, I'd like them to eat algae in my main tank, but that's also where my kubotai loaches are, and this batch of snails was originally meant to be breeding stock for loach treats.
Anyway, if anyone's looking for another source for olive nerites, check Carolina biological Supply Co., and look for "Physa" snails.