The microtubular organelles in the hypotrich ciliate Euplotes elegans were analyzed with fluorescence labeling of FLUTAX,anti-α tubulin and anti-centrin antibody.The results showed that these organelles consist of adoral zone of membranelles(AZM),undulating membranes(UM),frontal-ventral-transverse cirri(FVTC),marginal cirri(MC),caudal cirri(CC),dorsal kineties(DK)and the base associated microtubules of these ciliatures.The microtubular cytoskeleton of AZM comprises membranelle brackets and its associated microtubules;the base associated microtubules of FVTC contained anterior longitudinal microtubules(ALM),posterior longitudinal microtubules(PLM),transverse microtubules(TM)or radiating microtubules(RM).The base associated microtubules of the left MC and CC differentiated less obviously,and the basal bodies of DK contained rosette-like skeletal structure.All these microtubular structures together with the longitudinal microtubules and the transverse microtubules of dorsoventral cortex make up the cytoskeleton.Meanwhile,our results also indicate that the cytoskeleton of Euplotes is built up mainly with the microtubules as its major units,and the organization of its base-associated microtubules is quite different from other ciliates.Moreover,it was found that centrin existed in the anlagen and the basal bodies during the process of the morphogenesis,which might play a role in the maintenance of basal bodies and the assembly of microtubules.