An arrangement of diatoms from Singiliewsky, Russia. Prepared by Bernard Hartley. Mounted in Naphrax and dated August 1983. Olympus BHB microscope using 450nm LED light. 63x Leitz Pl Apo 1.4 objective, oil immersion. Olympus Aplanat Achromat condenser, oil immersion, brightfield lighting. 2.5x Nikon CF PL photoeyepiece. Monochrome converted Nikon d850. Stacks prepared in Zerene (Pmax).
Eunotogramma sp. Looking at examples, I think this is Eunotogramma gibbosa. Circular shadow in the central portion could be from another diatom which is just below it.
Sheshukovia flos. Fairly sure on this one.