Strew slide from Antarctica from the HMS Challenger expedition (1872-76). This slide is dated 8/[18]77 so was made just after the return of the expedition. It quite a low contrast slide, and I suspect this was just mounted in Canada Balsam. The image shows what I think is an Azpeitia sp. (maybe A. gombosi or A. elegantula). Olympus BHB microscope using 450nm LED light. 63x Leitz Pl Apo NA 1.40 objective, oil immersion. Olympus Aplanat Achromat condenser, oil immersion, very oblique lighting. 2.5x Nikon CF PL photoeyepiece. Monochrome converted Nikon d850 camera. 10 images stacked in Zerene (Pmax).