Figure 2: Light micrographs of the liver. Light micrographs of HHS and MMs in livers. (a) Several-cell-thick plate type. The hepatocyte lining is multi-layered. Hepatic sinusoids are narrow and short tortuous capillaries. The Black-headed sea snake (Hydrophis melanocephalus). (b) Two-cell-thick plate type. The hepatocyte lining is double-layered. Three to four hepatocytes surrounded a sinusoidal capillary. Japanese mamushi (Gloydius blomhoffii). (c) One-cellthick plate type. The hepatocyte lining is simple-layered. Hepatic sinusoids are enlarged. Japanese odd-tooth snake (Dinodon orientale). (d) HSS showed the combined one- and two-cell-thick plate types. PZ was the two-cell-thick plate type, whereas IZ and CZ were the one-cell-thick plate type and sinusoidal capillaries were enlarged. Peripheral sinusoids near terminal portal veins were tortuous, becoming straighter in the remainder of their course toward terminal central veins. MMs (arrows) were situated in the PZ and IZ. They were observed in sinusoidal capillaries, and various sizes existed. Red-eared slider (Trachemys scripta elegans). (e) HSS showed the one-cell-thick plate type. Sinusoidal capillaries were enlarged. MMs (arrows) were situated in the three zones (PZ, IZ, CZ). They were observed in sinusoidal capillaries, and small sizes existed. Japanese skink (Plestiodon japonicas). (f) MMs (arrows) were situated in the three zones (PZ, IZ, CZ). They were observed in sinusoidal capillaries, and large sizes existed. House gecko (Hemidactylus frenatus). (g) MMs (arrows) were situated in the IZ and CZ. They were observed in brown cytoplasmic phagosomes, and were of a small size in sinusoidal capillaries. Sakishima grass lizard (Takydromus dorsalis). P: portal triads CV: central vein Scale bar=50 μm.