According to a news item in American Paleontologist (v. 7, no. 1, p. 14;
Feb. 1999), Frank Wesselingh and Edmund Gittenberger recently discovered a
Miocene land snail from the Amazon region of Colombia. They reported
specimens up to 25.6 cm long (about 10 inches). Unfortunately, they were
not able to collect complete specimens. The full report is in Veliger (v.
42, p. 67; 1999), a journal that, unlike Doug Shelton's Malacological
Expositor, does exist, although not in any of the local libraries.
 
That's a pretty big snail, and I have to wonder how large its radula was.
Here's a question for the gastropodologists: Is there any relationship
between the size of a snail's shell and the size of its radula?
 
Andrew K. Rindsberg
Geological Survey of Alabama
Tuscaloosa, Alabama, USA