The slow swimming mutant (strain 11C 104), isolated from Paramecium caudatum, which swims at a speed about 70% of the wild type, is not different from the wild type (strain Kyky-1) in cell shape, density of cilia over the cell surface, and length of cilia. Cross-sectioned structures of the somatic cilia also do not give any difference between the mutant and the wild type. ATPase activities of c...