Stauroneis fulmen (written as fulmens on the label). Single example on the slide. Prepared by John Thomas Norman. Olympus BHB microscope using 450nm LED light. 40x Leitz Pl Apo 1.00 objective, oil immersion. Olympus Aplanat Achromat condenser, oil immersion, oblique lighting. 2.5x Nikon CF PL photoeyepiece. Monochrome converted Nikon d850 camera. 38 images stacked in Zerene (Pmax).
Stauroneis fulmen Brightwell 1859. Published in: Brightwell, T. (1859). On some of the rarer or undescribed species of Diatomaceae. Part I. Quarterly Journal of Microscopical Science, London 7: 179-181, pl. IX. Page 180, Plate IX (9), Figure 6 (a really nice image of it).