Brightwellia rossica from Singiliewsky (spelt Singiliewski on the slide). Single example on the slide and it is slightly tilted. Some issues with the mountant. No details on the mountant . 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).
Brightwellia rossica Pant. is mentioned In Diatomées du monde entier : Collection Tempère et Peragallo, by Tempère, J. (Joannes). 1915. p.141. Location: Kusnetzk (Russie), Dépôt fossile marin. It gives the reference for this as – J. Pantocsek. Diatomées fossiles de Hongrie. Volumes II et III. However I can’t find a copy of this to check. Looks like Brightwellia coronata to me.
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.