Raphoneis amphiceros from ‘La Gard (?), France’. Single example on the slide. No makers name given, but it is the same style and handwriting as a slide prepared by Sidney Chaffers. 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. 17 images stacked in Zerene (Pmax).