Coscinodiscus elegans from Springfield, Barbados. Single example on the slide, viewed from the underside (rim towards the coverslip). Unknown slide maker. Oddly low contrast, not sure why. 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. 42 images stacked in Zerene (Pmax).
Described in Greville, R.K. (1866). Descriptions of new and rare Diatoms. Series XIX. Transactions of the Microscopical Society, New Series, London, 14: 77-86, pls VIII & IX. page: 79; pl. 8, fig. 13.
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.