Abstract: During the asexual division of Stylonychia mytilus, holes were observed on the surface of cell pellicle in the anlagen region by using scanning electron microscope. Then, cilia buds extended from each hole and formed the anlagen region of new ciliatures; 1/3 part of the old adoral zone of membranelles (AZM) was renewed, together with the leftever constitute an intact AZM at the original area which belonged to the proter; The new marginal cirri primordium presents in the front and the middle part of the degenerated site of the old marginal cirri, after that, the new marginal cirri formed at the right area but not the originally area of the old ones. These results show that during the process of morphogenesis, the basal bodies form below the surface of cell pellicle; the constitution of AZM in the proter is related to the renewal of the old AZM, the old cilias which belong to the anlagen region played an important part in the location and orientation of the new structure, what′s more, supplied its development with some substances.

Key words: morphogenesis, scanning electron microscope (SEM), Stylonychia mytilus, morphogenesis, scanning electron microscope (SEM)