Two examples of Pleurosigma sinense mounted in Styrax. Prepared by Watson and Sons Ltd. Olympus BHB microscope using 450nm LED light. I imaged the smaller one using a 63x Leitz Pl Apo NA 1.4 objective, oil immersion. Olympus Aplanat Achromat condenser, oil immersion, oblique lighting. 2.5x Nikon CF PL photoeyepiece. Monochrome converted Nikon d850 camera. 39 images stacked in Zerene (Pmax). This was a quite low contrast slide.
I am working on the assumption that P. sinensis and P. sinense are the same thing. Pleurosigma sinensis (Ehrenberg) Ralfs 1861. Published in: Pritchard, A. (1861). A history of infusoria, including the Desmidiaceae and Diatomaceae, British and foreign. Fourth edition enlarged and revised by J. T. Arlidge, M.B., B.A. Lond.; W. Archer, Esq.; J. Ralfs, M.R.C.S.L.; W. C. Williamson, Esq., F.R.S., and the author. pp. [1]-xii, [1]-968, 40 pls [I-XV]. London: Whittaker and Co.. Page 916. This name is currently regarded as a synonym of Gyrosigma sinense (Ehrenberg) Desikachary. Source of synonymy: Desikachary, T.V. (1988). Marine diatoms of the Indian Ocean region. In: Atlas of Diatoms. Fasc. V. pp. 1-13, pls 401-621. Madras: Madras Science Foundation.