Fig. 1
From: Analysis of septal spacing and septal crowding in Devonian and Carboniferous ammonoids
A Mature specimen of Ceratites nodosus with terminal septal crowding (from von Buch, 1849). B Longitudinally sectioned specimen of Nautilus pompilius (specimen MB.C.30283, from unknown locality) with shortened terminal phragmocone chamber and thickened wall of the terminal septum