Although not labelled with the species, I am fairly sure this is Trigonium lineatum from Oamaru, New Zealand. Mounted in between three other diatoms. Prepared by Ernest Wainwright. Dated May 1942. Olympus BHB microscope using 450nm LED light. 63x Leitz Pl Apo NA 1.40 objective, oil immersion. Olympus Aplanat Achromat condenser, oil immersion, oblique lighting. 2.5x Nikon CF PL photoeyepiece. Monochrome converted Nikon d850 camera. 27 images stacked in Zerene (Pmax).