Fine structure of the epithelium of the gut in the crayfish (Procambarus clarkii) with special reference to the cytoplasmic microtubules.

The gut of the Decapod has been known to show many differences in histological structure from that of vertebrates; i. e., the foregut and hindgut of the Decapod possess cuticular coats composed of protein ground substance with chitinous fibrils, on the luminal surface of the gut epithelium, whereas the midgut lacks it (HUXLEY, 1881). Furthermore it has been reported that the muscle fibers of the gut wall attach themselves to the epithelium in the hindgut (VITZOU, 1882) and also are attached to the cuticle by their tendons running upwards between the epithelial cells (FRENZEL, 1885). Thus the Decapod may, from the viewpoint of comparative anatomy, provide some interesting information on the structure and function of the intestine. However, very little is known about the fine details of the interesting structure of the Decapod gut at the electron microscopic level. The present work deals with the fine structure of the epithelium in the midgut and hindgut of the crayfish.