A really nice arrangement of 49 diatoms from Palos Verdes, California, USA in a 7×7 grid. Mounted in Styrax and dated 1946. Mountant has yellowed. No makers name, but looks to be the same person that made this. Olympus BHB microscope using 450nm LED light. As well as the arrangement I imaged one, an Asterolampra marylandica (5th row down, 2nd from the left), with the 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. 25 images Pmax. Underside view, rim upwards. Quite low contrast likely due to the Balsam mountant.
Asterolampra marylandica Ehrenberg 1844. Published in: Ehrenberg, C.G. (1844). Mittheilung über 2 neue Lager von Gebirgsmassen aus Infusorien als Meeres-Absatz in Nord-Amerika und eine Vergleichung derselben mit den organischen Kreide-Gebilden in Europa und Afrik. Bericht über die zur Bekanntmachung Geeigneten Verhandlungen der Königl. Preuss. Akademie Der Wissenschaften zu Berlin 1844: 57-97.