An arrangement of nine Polymyxus coronalis (spelt Polymyxos on the slide) from the Pará River, Brazil. No makers name but I understand this was made by Frederick Marshall. 63x Leitz Pl Apo 1.4 objective, oil immersion. Olympus Aplanat Achromat condenser, oil immersion, brightfield lighting. 2.5x Nikon CF PL photoeyepiece. Monochrome converted Nikon d850 camera. Image of the one in the 9 o’clock position from the arrangement. 66 images stacked in Zerene (Pmax).
Some more information about this diatom in: J. Nelson Navarro & Rosa G. De Peribonio (1993) A light and scanning electron microscope study of the centric diatom Polymyxus coronalis (Bacillariophyta), European Journal of Phycology, 28:3, 167-172, DOI: 10.1080/09670269300650261.