Biddulphia fossa single example on the slide, mounted with the rim facing the coverslip (underside view). Label also says Anaulus (see below regarding this) and Glyphodiscus stellatus (not sure as to why as there isn’t one on the slide). Some issues with the mountant/adhesive to the coverslip. No location or mountant given. Unknown maker. Olympus BHB microscope using 450nm LED light. 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. 86 images stacked in Zerene (Pmax).
Biddulphia fossa Grove & Sturt 1887. Published in: Grove, E. & Sturt, G. (1887). On a fossil marine diatomaceous deposit from Oamaru, Otago, New Zealand. Appendix. Journal of the Quekett Microscopical Club, Series 2 3(19): 131-148, pls 10-14. Page 133, Plate 10, Figure 15. This name is currently regarded as a synonym of Anaulus fossus (Grove & Sturt) Grunow. Source of synonymy: Grunow, A. (1888). Referate. Grove, E. and Sturt, G. On a fossil marine diatomaceous deposit from Oamaru, Otago, New Zealand (Journal of the Quekett Microscopical Club. Ser. II Vol. III. No. 18 and No. 19.1887. Part III and appendix.). Botanisches Centralblatt 34(2/3): 34-41.
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.