Triceratium radians from Sendai, Japan. Single example on the slide. ‘Cover gug’ (presumably Coverslip gauge/thickness) 0.004” (0.16mm). Dated 1896 (maybe February 1896). Prepared by William Allott Firth. Olympus BHB microscope using 450nm LED light. 63x Leitz Pl Apo NA 1.4 objective, oil immersion. Olympus Aplanat Achromat condenser, oil immersion, oblique lighting. 2.5x Nikon CF PL photoeyepiece. Monochrome converted Nikon d850 camera. 70 images stacked in Zerene (Pmax).
I am working on the assumption that this is Triceratium radians J.A.Tempère & Brun. Published in: Schmidt, A.[W.F.] (1891). Atlas der Diatomaceen-kunde. Series V: Heft [41/42]. pp. pls 161-168. Leipzig: Fues’s Verlag (R. Reisland). Plate 166, Figure 5.