Fig. 3

Serial sectioning for multiple experiments. Sagittal sections spanning midfacial tissue between the eyes were analyzed. Sagittal sections along the medial–lateral axes are shown for C. perspicillata at CS16 (a). Shown is slide series 10 stained with H&E and counterstained with alcian blue (b) for anatomical reference. Slide series 1 is used for immunohistochemistry (c) to target proliferating cells. Sagittal sections imaged at 20× magnification are positioned along the medial–lateral axis to visualize developing cranial tissue. H&E staining highlights the cytoplasm of cells in pink (eosin); cartilage cells in blue (alcian); and nuclei are stained black (hematoxylin) (d). Scale bar: 1 mm