Morphogenesis of the Septum in Ammonoids

摘要: Ammonoid septa are aragonitic structures that divide the shell internally into a series of chambers, most adorai which (also largest one) is living chamber and occupied by ammonoid’s soft body. The septal surface roughly transverse to tube. typical feature septum its marginal corrugation. Individual folds given different names according their polarity. Adorally bulging major called saddles, apically directed lobes. Minor elements saddles lobes folioles lobules, respectively. Marginal complication progressively decreases toward center, slightly undulated flat surface. For each saddle or lobe, fold element placed opposite (i.e., linked minimal distance through other side wall whorl cross section) always same polarity (Figs. 9, 10). Therefore, adorally concave when sectioned across two convex this done On basis property, an anticlastic