An Oamaru type slide (unfortunately, it is not in a good way). Issues with the mountant and lots of movement. Unknown maker. Olympus BHB microscope using 450nm LED light. I selected an example of Stictodiscus californicus var. nitida for imaging at higher resolution with a 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. 30 images stacked in Zerene (Pmax).
Stictodiscus californicus var. nitida Grove & Sturt 1887. Published in: Grove, E. & Sturt, G. (1887). On a fossil marine Diatomaceous deposit from Oamaru, Otago, New Zealand. Part III. Journal of the Quekett Microscopical Club, Series 2 3: 63-78, pls 5, 6. Page 66, Plate 5, Figure 7. Synonym: Stictodiscus nitidus Grove and Sturt (1888), in Schmidts Atlas Plate 131 Figures 7,8, Plate 202 Figures 4,5, Plate 451 Figures 5-7.
I recently acquired about 30 more slides by this maker to add to the ones I already had, so if you want to see others by them, search for AAAAA in the Search option at the top of the page, and I’ll include this in each of the pages for them.