A Scanning Electron Microscope Study of the Frustule Structure of the Freshwater Diatom Melosira Granulata (Ehr.) Ralfs

Frustules of the freshwater diatom Melosira granulata (Ehr.) Ralfs from a freshwater diatomite of Miocene age and recent frustules of this species from Reelfoot Lake, Tennessee were examined under a scanning electron microscope to determine fine structure generally not seen or poorly seen with the conventional light microscope.The terminology used to describe frustule structure in this study was originated by Hendy.Melosira granulata generally grows in chains of two connected frustules with each frustule containing two valves or halves. The connection between frustules is accomplished by the encasing of the adjacent valves of two frustules by a structure called the girdle (Fig. 1a).