A slide of Tetracyclus rupestris from the Garda Lake, Italy. A range of them in between two Eupodiscus diatoms. No makers name. Olympus BHB microscope using 450nm LED light. As well as an image with a 10x Nikon Plan Apo NA 0.45 objective, I imaged a few using the 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. 23 images stacked in Zerene (Pmax). Small diatoms.
Tetracyclus rupestris (Kützing) Grunow 1881. Published in: Van Heurck, H. (1881). Synopsis des Diatomées de Belgique Atlas. pp. pls XXXI-LXXVII [31-77]. Anvers: Ducaju et Cie. Plate pl. LII [52], Figures 13,14. Homotypic synonyms: Denticula thermalis var. rupestris Kützing 1849, Gomphogramma rupestre (Kützing) A.Braun ex Rabenhorst 1853.
I have recently imaged a few slides by this maker, all of which are nice. If you want to see others search for CCCCC in the ‘Search’ function.