What are the ribs like?
- All of the ribs are large and similar in form.
- The ammonite has a few large ribs seperated by many fine, packed ribs.
- All of the ribs only cross half the shell due to a groove on the flank.
- The ammonite has simple ribs that are spaced out. (It also has a keel.)
- The shell is packed with many fine ribs.
