A group of Surirella sp.. No makers name, and no obvious location (although it does say HK, so maybe Hong Kong?). Olympus BHB microscope using 450nm LED light. 40x Leitz Pl Apo NA 1.00 objective, oil immersion. Olympus Aplanat Achromat condenser, oil immersion, oblique lighting. 2.5x Nikon CF PL photoeyepiece. 11mm removed from the tube to the camera to increase the field of view. Monochrome converted Nikon d850 camera. 26 images stacked in Zerene (Pmax).
As for what these are, maybe Surirella patens (Schmidt’s Atlas Plate 4, Figure 17) but this is very tentative. Hhis species has apparently been collected from waters around Hong Kong (reference for this may be Mann 1925, Philippine diatoms, but that could be AI generated and I need to verify).