Abstract
Sporulation of putrefactive anaerobe 3679h was studied by observation of ultra-thin sections in the electron microscope. The customary stages were observed during forespore formation, spore maturation, and liberation of the free spore. The exosporium was partially laminated and devoid of the hairlike surface projections observed on spores of some species. Atypical membrane configurations occurred in some cells, and, occasionally, cells with bipolar forespores were found.