An example of Monopsia mammosa from Allan’s Farm, Oamaru, New Zealand. Spelt Monopsis on the label. Single diatom on the slide, mounted with the rim to the coverslip (underside view). Very ‘orange’, I think it has picked up some of the dye from the ring around the diatom. No details on the mountant used. Unknown maker. Olympus BHB microscope using 450nm LED light. 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. 56 images stacked in Zerene (Pmax). I’ve also included two other stacks, looking in more detail at the oculus. One shows the underside level (‘inside’ if viewed from above), and the other the top layer (the ‘outside’ if viewed from above).
Monopsia mammosa Grove & Sturt 1887. Published in: Grove, E. & Sturt, G. (1887). On a fossil marine diatomaceous deposit from Oamaru, Otago, New Zealand. Appendix. Journal of the Quekett Microscopical Club, Series 2 3(19): 131-148, pls 10-14. Page 142, Plate XIII, Figure 38. Also see: “The diatom genus Monopsia Grove and Sturt: morphology, classification and a note on the relevance of fossil characters”, Pat A. Sims & David M. Williams, Nova Hedwigia, 2021, Beiheft 151, p. 249–259.
I recently acquired about 30 more slides by this maker to add to the ones I already had, so if you want to see others by them, search for AAAAA in the Search option at the top of the page, and I’ll include this in each of the pages for them.