Abstract
Morphological studies were made on the minute crescent-shaped organism, which has been called Spirillum sputigenum or Selenomonas sputigena. In the light microscopic observations with flagella staining or in the electron microscopic observations with shadow casted preparations, this organism seemed to be peritrichously flagellated. However, in the electron microscopic observations with negatively stained ghost cell, the origins of flagella were found to be localized on the middle two-third of concave side of the cell. These observations suggested that the organism should be named as Selenomonas sputigena. In the early stage of cell division of this organism, two daughter cells have been shown to have not only the same number of flagellum but almost the same length of it. The developing manner of flagellum in dividing state of this organism was different from the condition of Salmonella typhi, Proteus vulgaris and Pseudomonas fluorescens as described by Bisset (1951). Selenomonas sputigena showed constantly semilunar or kidney form even in dividing state, and sigmoidal cell form was not observed in any cases.
