586 A peculiar odour that prevails in marshy areas and cow-sheds is on account of a gas produced by

Archaebacteria is primitive group of bacteria. The three main groups of archaebacteria are methanogens, halophiles and thermoacidophiles. Methanogens are obligate, anaerobic archaebacteria which oxidize CO2 during cellular respiration to produce methane as a waste product. They are found in the musk of swamps and marshes, the rumen of cattle sewage sludges and gut of termites, e.g., Methanococcus jannaschii, Methanobacterium.