A slide with two examples of Navicula crabro. Current name Diploneis crabro. Prepared by Samuel Henry Meakin. Mounted in Hyrax and dated October 1932. A black residue came off when cleaning off the immersion oil after imaging. I suspect the ring has been repainted at some point. 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. 34 images stacked in Zerene (Pmax).