An arrangement of three Coscinodiscus ornatus, prepared by Samuel Henry Meakin. No details on the mountant or when it was made. Some crystallization of the mountant and, one of the diatoms looks to have drifted from its intended position. I chose this one to image further. Olympus BHB microscope using 450nm LED light. 63x Leitz Pl Apo 1.4 objective, oil immersion. Olympus Aplanat Achromat condenser, oil immersion, slightly oblique lighting. 2.5x Nikon CF PL photoeyepiece. Monochrome converted Nikon d850 camera. 61 images stacked in Zerene (Pmax).
This diatom is also known as Actinocyclus ornatus. All 3 examples on the slide have the ‘Actinocyclus’ hole near the rim, the one in main image near the 9 o’clock position. As such, personally I think these are more Actinocyclus than Coscinodiscus.