Fig. 3. Schematic construction of the dorsal shell wall (A, D, E, median section, growth direction right, centrifugal; B, C, F, G, transversal section, centrifugal). A, B. Complete dorsal shell wall. D, G. Seemingly complete dorsal shell wall. C. Complete dorsal shell wall of Amaltheidae. E, F. Reinforced complete dorsal shell wall. Abbreviations: dipl, dorsal inner prismatic layer; dipl 1/2, primary/secondary dorsal inner prismatic layer; dncl, dorsal nacreous layer; dncl 1/2, primary/secondary dorsal nacreous layer; dopl, dorsal outer prismatic layer; ipl, inner prismatic layer; ipl 1/2, primary/secondary inner prismatic layer; ncl, nacreous layer; ncl 1/2, primary/secondary nacreous layer; opl, outer prismatic layer; so, spiral ornament; vsw, ventral shell wall of the preceding whorl; wl, wrinkle layer.

Published as part of Radtke, Gregor & Keupp, Helmut, 2017, The dorsal shell wall structure of Mesozoic ammonoids, pp. 59-96 in Acta Palaeontologica Polonica 62 (1) on page 61, DOI: 10.4202/app.00263.2016, http://zenodo.org/record/10980781