The fine structure of two unusual stalked bacteria.

Two strains of bacteria that produce slender appendages (pseudostalks) from their lateral surfaces were studied using the electron microscope. The pseudostalks were shown to be extensions of the cytoplasm and peripheral membranes of the cell proper. Both strains of bacteria produce holdfasts at the poles of the cells by the means of which attachment can take place. The pseudostalks are not involved in the attachment of cells. No specialized intracytoplasmic structures are present at the point of juncture of pseudostalk and cell. A discussion of the possible functions of the pseudostalks, based on the electron microscope findings, is presented.