An arrangement of three Cocconeis regalis. The one at the top is an underside view with the rim upwards and an issue with the mounting. The two at the bottom a ‘top views’ with the rims down. The one at the lower left is tilting down a bit towards its top right. A ‘two dot’ slide. Prepared by Edmund Wheeler. Olympus BHB microscope using 450nm LED light. 63x Leitz Pl Apo 1.40 objective, oil immersion. Olympus Aplanat Achromat condenser, oil immersion, oblique lighting. 2.5x Nikon CF PL photoeyepiece. Monochrome converted Nikon d850 camera. 69 images stacked in Zerene (Pmax).
Cocconeis regalis Greville 1859. Published in: Greville, R.K. (1859). Description of Diatomaceae observed in Californian guano. Quarterly Journal of Microscopical Science 7: 155-166. Page 156, Plate 7, Figure 1. This name is currently regarded as a synonym of Campyloneis grevillei (W.Smith) Grunow & Eulenstein 1868. Published in: Grunow, A. (1868 ‘1867’). Algae. In: Reise der österreichischen Fregatte Novara um die Erde in den Jahren 1857, 1858, 1859 unter den Befehlen des Commodore B. von Wüllerstorf-Urbair. Botanischer Theil. Erster Band. Sporenpflanzen. (Fenzl, E. et al. Eds), pp. 1-104. Wien [Vienna]: Aus der Kaiserlich Königlichen Hof- und Staatsdruckeri in Commission bei Karl Gerold’s Sohn. Page 10.
I am not convinced that these are the same as ones labelled Campyloneis grevillei (for example here).
EDIT 30/7/2026
Since making this page I have imaged another Cocconeis regalis slide, this time by Flatters and Garnet Ltd.
Not the best image, as the mountant was very orange, and the diatoms too deep for the 40x and 63x Leitz immersion objectives. However these look different to the ones on the Wheeler slide. These look more similar to my examples of Campyloneis grevillei. Based on this I am less sure of the Cocconeis regalis name for the ones on the Wheeler slide.