Triceratium sp. (I think probably T. favus) from Thames mud. Single example on the slide mounted with the rim upwards towards the coverslip. No makers name, but ‘Triceratium from Thames mud’ and ‘149’ diamond scratched onto the slide. Also the small ring around the diatom is scratched on and is on the underside of the slide, not the top side with the diatom. I presume this is because it would be lost a bit with the mountant over it. The diatoms processes were all visible in the individual frames before stacking, but were lost in the final image.
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. 41 images stacked in Zerene (Pmax).