Abstract: The cortical microtubular organelles of hypotrichous ciliate Euplotes eurystomus were visualized by using FLUTAX direct-fluorescent labeling. These organelles were composed of ciliature microtubules, ciliature baseassociated microtubules and cortical non-ciliated regions microtubules. The ciliature microtubule and ciliateure base-associated microtubule consists of adoral zone of membranelles(AZM) and membranelle brackets microtubules; undulating membrane(UM) and its base-associated microtubule nets; frontal-ventral-transverse-caudal-cirri (FVTCC), left marginal cirri (LMC) and the anterior longitudinal microtubules(ALM), posterior longitudinal microtubules(PLM),transverse microtubules(TM); the dorsal kineties (DK) and the rosette-like skeletal structure. The cortical non-ciliated regions microtubule comprises leptos microtubule nets in the dorsal and ventral cortex; the oblique microtubules in the dorsal cortex; and the longitudinal microtubules. During the process of the morphogenesis of the ciliatures, the AZM of proter is generated from the old AZM. The old ciliature base-associated microtubules degenerate as the FVTCC of proter and opisthe morphogenesis and differentiate. The old cirri and its associated microtubules might play a role of orientation and localization, but without direct physical contribution. The results provide data for the understanding of the construction of cortical microtubular organelles, the differentiation of cortical microtubules and the regulation of cell in ciliates.

Key words: Euplotes eurystomus,  cortical microtubular organelle, cortical nonciliated regions microtubule, morphogenesis, ciliate, Euplotes eurystomus,  cortical microtubular organelle, cortical nonciliated regions microtubule, morphogenesis