An arrangement of Coscinodiscus sp. (label says C. heteroporus, but I have an example of that on this slide and these don’t look very much like it, so I am not convinced). No makers name or location. Olympus BHB microscope using 450nm LED light. Couldn’t get close enough to use my 40x or 63x Leitz objectives, so had to image these with a 20x Nikon Plan Apo NA 0.65 objective. Olympus Aplanat Achromat condenser, oblique lighting. 2.5x Nikon CF PL photoeyepiece. Monochrome converted Nikon d850 camera. 16 images stacked in Zerene (Pmax). Quite a low contrast slide.