Fig. 7From: Analysis of septal spacing and septal crowding in Devonian and Carboniferous ammonoidsBivariate plots of phragmocone diameter and septal spacing of all analysed specimens (n = 470). A Septal spaces of all septa in the last half volution. B Septal spaces of the last three septa. C Difference in the septal spaces of the last three septa all septa in the last half volutionBack to article page