Preliminary Observations on the Fine Structure of Species of

THE GENUS M ieromonospora was first described by 0rskov in 1923 as a member of the Acti-nomycetales characterized by unicellar mycelium and the production of single, terminal conidia. The genus was little known for some time (Jensen, 1930), but subsequently the frequent occurrence of micromonosporae in soil (Jensen, 1932) , lake bottoms (Erikson, 1941; Potter and Baker, 1956) and lake water (Potter and Baker, 1956) , became well recognized. In spite of this wide acquaintance with the genus, the general morphology and cell structure is still not well understood and descriptions are some-times at variance. The chemical composition of the actinomycete wall, including micromono-sporae, (Erikson, 1947; Avery and Blank, 1951; Yamaguchi, 1965) is better documented than is the general morphology of the cell structure. Ultrastructure studies are few to date, and provide little detail (Agre, 1962; Leude-mann and Brodsky, 1964). Both of these studies were concerned primarily with spores. A paper by Arai, Koyama, Kuroda, and Honda (1964) is more definitive for both mycelium and spores. It also includes some electron micrographs