Figure 6: Histochemistery of protein secreting cells in red tail shark. A and B: The skin stained with Mallory triple stain showing red serous goblet cells (black arrowheads) and blue mucous goblet cells (white arrowheads). C: The skin stained with bromophenol blue showing serous goblet cells (arrowheads) and positive stained club cells (CC). D: The skin stained with Performic acidmethylene blue showing positive stained serous goblet cells (arrowheads).