A ‘Test’ strew slide containing Pleurosigma balticum. Coverslip 0.16-0.17mm. Mounted ‘Dry’. Prepared by Eduard Thum, and distributed by C Baker, London. Olympus BHB microscope using 450nm LED light. 20x Nikon Plan Apo 0.65 objective. Olympus Aplanat Achromat condenser, oblique lighting. 2.5x Nikon CF PL photoeyepiece. Monochrome converted Nikon d850 camera. 40 images stacked in Zerene (Pmax). The coverslip is cracked, radiating out from the middle in various directions. I didn’t risk oil immersion with it.
Pleurosigma balticum (Ehrenberg) W.Smith 1852. Published in: Smith, W. (1852). Notes on the Diatomaceae with descriptions of British species included in the genus Pleurosigma. Annals and Magazine of Natural History, Series 2 9: 1-12, 2 pls. Page 8, Plate 2, Figure 1. This name is currently regarded as a synonym of Gyrosigma balticum (Ehrenberg) Rabenhorst.