Auliscus caballi from Maria Madre island, Mexico. Fossil marine. Single example on the slide. Prepared by ECP Bone. Mounted in Naphrax and dated June 1969. 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. 33 images stacked in Zerene (Pmax).
This one does appear in Schmidt’s Atlas (Schmidt, A. (1875). Atlas der Diatomaceen-kunde. Aschersleben, Commissions-Verlag Von Ludwig Siever’s Buchandlung. Series I (Heft 8): pls. 29-32. page(s): Plate 32; Figs 1, 2.). Google translate of what it says is as follows (number in brackets presumably relate to Figs 1 and 2); “The sculpture, which almost disappears in the balsam preparation (2), is only faintly visible even in the dry preparation (1). Related to A. elaboratus Ralfs, but its processes are not surrounded by an oval-defined aureole, as in that one.”. This sounds like it was tricky to image for Schmidt, but the high RI Naphrax mount on this slide will have helped me with this one.