Not much to go on with this slide. Simply labelled Aulacodiscus. Single example on the slide. No makers name and dated 11/7/44. To me it looks like an A. grunowii. 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. Monochrome converted Nikon d850 camera. 96 images stacked in Zerene (Pmax).
I am leaving this as ‘unknown maker’ at the moment, however I have slides of a very similar style by the Manchester Microscopical Society, and Sidney Chaffers.