a group of bacteria, whose cell form and life cycle resemble those of mycobacteria. A number of their biochemical and physiological characteristics differ from those of mycobacteria. These bacteria are apparently related to the actinomycetes. The best-known representative of Corynebacteria is Corynebacterium diphtheriae, the causative agent of diphtheria. This bacterium contains the nuclei of volutin at the end of the cells; a powerful toxin forms that can cause paralysis of the soft palate, the extremities, and the heart muscle.