An arrangement of four Pleurosigma balticum, from the estuary of the River Tay, Scotland. Mounted in a ‘new mountant’. Serious issues with the new mountant; crystallisation, cracked coverslip, yellowing. Dated 11/1897. Prepared by William Allott Firth. 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. 24 images stacked in Zerene (Pmax).
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, 1853. Published in: Rabenhorst, L. (1853). Die Süsswasser-Diatomaceen (Bacillarien.): für Freunde der Mikroskopie. pp. [1]-xii, [1]-72, 10 plates [I–X]. Leipzig: Eduard Kummer. Page 47, Plate 5, Figure 6.