Figure 59: Intercalary chamberlets in Borelis curdica (Reichel). Qum Basin, Iran. Allemann collection 229. Lower Miocene. Axial section.
chl: chamberlet; f: foramen; ichl: intercalary chamberlet; if: intercalary foramen; prp: preseptal passage; s: septum; sl: Y-shaped septulum.