Abstract: Transmission electron microscopy reveals:(1) At the non-ciliated regions of this organism,under the pellicles of both dorsal and ventral cortex,there are longitudinal microtubule (MT) layers arranged in regular intervals:3 MT per unit under dorsal pellicle,and 1 MT per unit under ventral pellicle,while under dorsal ridge pellicle,10-20 MT per unit.Still,under all these MT layers,there are deeper MTs and cortical mitochondria.(2) High electron-dense rods are present in the oral cortex.In cortex of ciliated regions,besides pellicles,basal bodies,and their related structures,there are membranelle bracket (formed by the connection of electron-dense bands with cylindrical fibrous matters) at the base of AZM membranelles.On both sides of ciliated basal bodies of cirral regions,there are surrounding fibrillar cirral baskets,formed by basal body brackets and MT ribbons under basal bodies.Still,beneath these brackets,there are again MT ribbons.Among these MTs under basal bodies of dorsal cilia,some of them extend near to the MT ribbons under pellicle ridges.(3) Within the macronucleus,many chromatin attached to nuclear membrane,and many regularly arranged nuclear pores scattered on other regions of the membrane.