Three morphological mutant clones were isolated from C6 glioma cells. They were named C6F, C6L and C6D, respectively. C6F cells were flat and polygonal, similar to the original C6 cells, though they formed fluffy colonies. C6L cells were long, thin and bipolar and formed colonies of linearly arranged cells. Most C6D cells were unipolar or bipolar, though some were multipolar, and formed dispersed colonies. All these mutant clones as Well as original C6 cells differentiated morphologically in the stationary phase. In suspension culture, all the