CYMATOPLEURA SOLIA DIATOM

In the center of this diatom is an area used for testing objectives. The coarse striations are called costae or ribs. These are seen even with a 10X objective. The finer striations are just resolved with green darkground illumination at 40X with na of 0.70. These are seen well with double oil immersion with dark ground illumination and are more striking in green oblique light or DIC. The puncta within these thinner striations require electron microscopy to visualized. Visualization of the fine striations of this diatom require high refractive index mountant, e.g. 1.7. The areolae of this diatom are tiny, lie along the thin striae and cannot be visualized except with the electron microscope.