The liver lobule of Eel (Anguilla japonica Temminck and Schlegel) is irregular in form. The hepatocytes are rich in mitochondria, rough and smooth endoplasmic reticulum, ribosomes, glycogen and lipid droplets. The bile canaliculi consist of two to four adjacent hepatocytes. Tight junctions, intermediate junctions and desmosomes occur between the adjacent hepatocytes. The hepatic sinusoids are fenestrated, containing kupffer cells. No diaphragms are bresent in fenestra. The perisinusoidal space of Disse is clear. On the surface of hepatocytes, there are many finger microvillia facing the bile canaliculi and the perisinusoidal space of Disse. The trabeculae are seldom seen in spleen. The spleen is made up of two structures: the white pulp and the red pulp. The lymphocytes of white pulp aggregated into groups. The red pulp is made up of splenic cords and splenic sinusoid. The germinal center, periarterial lymphatic sheath are not clear. The terminal parts of splenic artery usually opened into the red pulp. The melanomacrophage centre is not clear. The end othelial lining cell of splenic artery and splenic sinusoid are usually elongated with tapered ends and parallel to the long axis of the blood vessels. The splenic sinusoids are fenestrated and each fenestra is usually closed by a thin single-layered diaphragm. The media under the splenic arterial endothelium contain two to five layers of smooth muscles cells (usually longitudinal muscles).