RH Whittaker (1969), an American taxonomist, divided all the organism into five kingdoms namely-Monera, Protista, Fungi, Plantae and Animalia. Kingdom-Monera includes all prokaryotes viz, mycoplasmas, bacteria, Actinomycetes and photosynthetic cyanobacteria. The nuclei of monerans are not organised with nuclear membrane, nucleoplasm, chromatic fibres and nucleolus and are referred as incipient nuclei.