The purpose of this study was to compare the histological features of pyloric caeca with that of the stomach and anterior intestine in Mugil cephalus. Specimens of M. cephalus were dissected and small pieces of each part were cut, fixed for routine histological procedures. The transverse sections were also stained by some stains for histochemical purposes. These sections were examined under a microscope, photographed, and described.
Histologically, the wall of the stomach, pyloric caeca, and anterior intestine in Mugil cephalus mainly consists of serosa, muscular, submucosa, and mucosa. While the stomach and pyloric caeca have deeply mucosal folds in a narrow lumen, the anterior intestine has a long mucosal fold protruding towards the wide lumen. The mucosa of the three organs consists of columnar cells and mucus cells; in addition to gastric glands in the proventriculus stomach only. The columnar cells at the gizzard stomach are lined toward the lumen with a continuous koillin layer. The mucus cells are medium in size and numbers at the anterior intestine and less at pyloric caeca, but it absent from the stomach. Lymphocytes and wandering cells are abundant in between columnar cells and in the submucosal layer. Histochemical differences between these three digestive organs were also studied and described.