SYNOPSISWith sunlight dark‐ground microscopy two new spirilla, one motile and the other not, at first showed typical single polar flagella and later polar flagella dissimilar in number, shape, size, and place of attachment. After that many frankly lateral flagella of various kinds arose, bringing about a peritrichous appearance. Finally the spirilla became covered with a mass of fibrils mixed with odd flagella. Cell walls of spirilla apparently contain a network of submicroscopic fibrils. These may become twisted into typical and atypical flagella and may also come off as masses of fibrils. None of these structures can be regarded as motor organ