No species indicated on the slide, but I think this is an arrangement of Triceratium intermedium. From Oamaru, New Zealand. Prepared by Ernest Wainwright. Dated July 1942. Olympus BHB microscope using 450nm LED light. 63x Leitz Pl Apo NA 1.40 objective, oil immersion. Olympus Aplanat Achromat condenser, oil immersion, brightfield lighting. 2.5x Nikon CF PL photoeyepiece. Monochrome converted Nikon d850 camera. 21 images stacked in Zerene (Pmax). Also shown is an unstacked image of one of the locating diatoms.