Entogonia sp. (likely E. formosa) from Hayti [Haiti]. Single example on the slide. Unknown maker. Olympus BHB microscope using 450nm LED light. 40x Leitz Pl Apo 1.00 objective, oil immersion (I couldn’t get deep enough with the 63x Leitz otherwise I would have used that). Olympus Aplanat Achromat condenser, oil immersion, oblique lighting. 2.5x Nikon CF PL photoeyepiece. Monochrome converted Nikon d850 camera. 75 images stacked in Zerene (Pmax).
There is a good review of this genus in: Holmes, R.W. & Brigger, A.L. (1979). The marine fossil diatom genus Entogonia Greville – A review. Bacillaria 2: 155-214. Based on this I think it is likely to be Entogonia formosa as Haiti is mentioned as a location for it, and it looks like it.
I recently acquired about 60 slides by this maker, 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.