Histological structure of the digestive tract of Pena us semisulcatus of Persian Gulf and Oman sea studied by stereo and light microscopy. The cardiac portion of the stomach is armed with dorsal, lateral and ventral chitinous ridges, teeth and hairs suitable for mechanical digestion . The pyloric stomach is divided by ridges in to an upper chamber through which most of the food passes in to midgut and a lower chamber containing only fluid and fine particles, which can enter to the hepatopancreas and digested with its enzymes and absorbed. Midgut is a long tube in which some digestion and absorbtion of food happened and the waste material eventually voided. The structure of the whole gut are described.