Figure 2: SEM micrograph of the oesophagus of Natrix tessellata, showing (a) primary and secondary folds. (Scale bar, 50 μm). (b) many goblet cells (Scale bar, 20 μm). (c) apical fingerprint-like microridge(MR) alternates with microvilli (MV) in some regions (Scale bar, 1 μm ).