Slide labelled Aulacodiscus sollittianus. Single example on the slide. 7 processes. Quite low contrast – mounted in Canada Balsam? No makers name but based on the handwriting it looks like Frederick Marshall. Olympus BHB microscope using 450nm LED light. 20x Nikon Plan Apo NA 0.65 objective. Olympus Aplanat Achromat condenser, oblique lighting. 2.5x Nikon CF PL photoeyepiece. Monochrome converted Nikon d850 camera. 39 images stacked in Zerene (Pmax). Couldn’t get close enough to use the 40x or 63x Leitz Pl Apo objectives.
Aulacodiscus sollittianus G.Norman, 1861. Published in: Norman, G. (1861). On some undescribed species of Diatomaceae. Transactions of the Microscopical Society, London, New Series 9: 5-9, pl. II. Page 7, Plate 2, Figure 5.