Triceratium favus var. septangulatum. Single example on slide. No location given. No makers name, but I understand this is by John Barnett. Olympus BHB microscope using 450nm LED light. 20x Nikon Plan Apo NA 0.65 objective. Olympus Aplanat Achromat condenser, slightly oblique lighting. 2.5x Nikon CF PL photoeyepiece. Monochrome converted Nikon d850 camera. 37 images stacked in Zerene (Pmax).
Triceratium favus var. septangulatum Kitton 1874. Published in: Kitton, F (1874). New Diatoms. Monthly Microscopical Journal 12: 218-220, pl. 81-82. Page 219, Plate 82, Figures 7,8. This name is currently regarded as a synonym of Triceratium grande var. septangulata (Kitton) Schmidt in Schmidt et al..