Fig. 2 in Aragonitic rostra of the Turonian belemnitid Goniocamax: Arguments from diagenesis

Fig. 2. Secondary electron images illustrating the microstructures of Recent shells. A. Dorsal shield of Sepia sp. (from New Caledonia), showing the thin inner prismatic layer, the nacreous layer and the thick multi−layered outer spherulitic prismatic layer. B. Outer wall of Spirula sp. (from New Caledonia), showing two prismatic layers and a mainly organic thin nacreous layer (arrow). C. Nautilus macromphalus (from New Caledonia). D. Nacreous layer of the pelecypod Pinna nobilis (from the Mediterranean Sea, Port Cros Island). E. Foliated calcite layer of Pecten maximus (from Brittany, France). F. Crossed lamellar aragonite layer of the gastropod Murex sp. (of unknown origin). Abbreviations: ip, inner prismatic layer; nac, nacreous layer; op, outer prismatic layer. All specimens from the UPS collection of Recent molluscs, not numbered.