Figure 4. Selachimorpha enameloid. A, P in Chondrichthyan tooth enameloid: past, present, and future

Figure 4. Selachimorpha enameloid. A, P. pockrandti, radial furrows near the SCE, transverse section etched 5 s in 10% HCl. B, P. jurensis, lingual ornament made of SCE, transverse section etched 5 s in 10% HCl. C, Sphyrna sp., cutting edge showing bundles of the PBE oriented normal to the axis of the cutting edge, transverse section etched 5 s in 10% HCl. D, Squatina sp., cutting edge showing bundles of the PBE oriented normal to the axis of the cutting edge, transverse section etched 5 s in 10% HCl.