Figure 3: EDS elemental mappings and profiles (line scans) on (A) BSE-SEM image of a polished cross-section of the spike cuticle. The dotted line represents the location where the profile plots in E and F were taken. (B-D) Elemental mapping of (B) calcium, (C) phosphorus and (D) carbon. Line scans of selected (E) major and (F) minor elements along the dotted line in (A) from the out surface towards the epidermis. IHR: inner helical region; HMR: highly mineralized region; OHR: outer helical region; STR: striated region. Scale bars: 50µm.