A strew slide from Mud from drain into The Wash, Lincolnshire. Good range of species. Material from H Gleave, collected October 1927. Mounted in Aroclor and dated May 1975. Prepared by Bernard Hartley. Olympus BHB microscope using 450nm LED light. I chose an example of a Surirella sp. (I think Surirella striatula) for high magnification imaging. 63x Leitz Pl Apo 1.4 objective, oil immersion. Olympus Aplanat Achromat condenser, oil immersion, oblique lighting. 2.5x Nikon CF PL photoeyepiece. Monochrome converted Nikon d850 camera. 46 images stacked in Zerene (Pmax).
Surirella striatula Turpin 1828. Published in: Turpin, P.J.F. (1828). Observations sur le nouveau genre Surirella. Mémoires du Musée d’Histoire Naturelle 16: 361-368. Page 363, Plate 15, Figures 2-10. To me it sort of looks like a variant as well – Surirella striatula var. gautieri Héribaud & Brun 1893. Published in: Héribaud-Joseph, Frère [J.-B. C.] (1893). Les Diatomées d’Auvergne. pp. [1]-255, 6 pls. Clermont-Ferrand & Paris: Pensionnat des Frères des Écoles Chrétiennes & Librarie des Sciences Naturelle. Page 178, Plate 1. However I am not sure about that, so will stick with S. striatula for now.
Although not numbered, based on the description I think this could be slides 659(B) from Bernard Hartley’s Sample and Strew Slide Collection PDF (accessed from here).