A slide of Pinnularia viridis and variants (LHS 3x Pinnularia viridis var. leptogongyla, middle 1x Pinnularia viridis var. commutata, and RHS, Pinnularia viridis). Mounted in Naphrax. Slide has broken and been stuck to another slide to make it usable. No makers name, but it looks like it could be Bernard Hartley based on the style. 40x Leitz Pl Apo NA 1.00 objective, oil immersion. Olympus Aplanat Achromat condenser, oil immersion, oblique lighting. 2.5x Nikon CF PL photoeyepiece. Monochrome converted Nikon d850 camera. 28 images stacked in Zerene (Pmax).
These are written about in Cleve, P.T. (1895). Synopsis of the naviculoid diatoms. Part II. Kongliga Svenska Vetenskapsak Akademiens Handlingar 27(3): 1-219, 4 pls. p.91, and I have included a screenshot of the relevant part.