I’ll come back to the name on the slide in a minute. Three examples of Melosira praeclara from Oamaru, New Zealand. Fossil marine material. Mounted in Hyrax. Prepared by Flatters and Garnett Ltd. Olympus BHB microscope using 450nm LED light. As well as the arrangement I imaged two using the 63x Leitz Pl Apo 1.4 objective, oil immersion. Olympus Aplanat Achromat condenser, oil immersion, oblique lighting. 2.5x Nikon CF PL photoeyepiece. Monochrome converted Nikon d850 camera. One, a top side view, was imaged using 33 images stacked in Zerene (Pmax). The other is a single frame which shows the underside view of the rim.
Back to the name. The slide says Orthosira sol. Orthosira sol (Ehrenberg) Grunow in Van Heurck, 1882. Parent: Orthosira W. Smith, 1855 accepted as Orthoseira G.H.K. Thwaites, 1848. Original name: Gaillonella sol Ehrenberg, 1844. Original description: (of Gaillonella sol Ehrenberg, 1844) Ehrenberg, C.G. (1844). Einige vorläufige Resultate seiner Untersuchungen der ihm von der Südpolreise des Capitain Rofs, so wie von den Herren Schayer und Darwin zugekommenen Materialien über das Verhalten des kleinsten lebens in den Oceanen und den gröfsten bisher zugänglichen Tiefen des Weltmeers. Bericht über die zur Bekanntmachung geeigneten Verhandlungen der Königlich-Preussischen Akademie der Wissenschaften zu Berlin, 1844: 182-207. Page 202, Plate 35. A. 23, Figure 12 (as ‘Gallionella‘). Available online at https://www.biodiversitylibrary.org/page/11052882. This name is currently regarded as a synonym of Ellerbeckia sol (Ehrenberg) R.M.Crawford & P.A.Sims, another name for which is Melosira sol.
However these are not Ellerbeckia sol. These are Melosira praeclara A.W.F.Schmidt, 1892. Published in: Schmidt, A.[W.F.] (1892). Atlas der Diatomaceen-kunde. Series IV: Heft 45/46 . pp. pls 177-180. Leipzig: O.R. Reisland. Plate 179, Figures 4,5. Homotypic synonym: Lysigonium praeclarum (A.W.F.Schmidt) Kuntze 1898.