Definitely my Triodopsis is Triodopsis tridentata. I have to find time to update this blog with many new photos and thoughts on snails. But I'm not because I'm working on an awesome snail iPhone app to help me with identifications. For now I'm only going to create a database with the known PA snails. But eventually I'd like to add all eastern snails, then all North America. It's pretty awesome. It also will double as a specimen log. It'll take a while, however, to research the database. The app doesn't really get me to an identification, but narrows it down as much as possible based on some key elements.
Here's a screen shot of the app: