Cestodiscus peplum var. from Conset, Barbados. Single example on the slide. Fossil marine material. Sty.Aro. (Styrax Aroclor) mountant, and dated September 1965. Prepared by ECP Bone. 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 d850 camera. 31 images stacked in Zerene (Pmax). The ‘spikes’ were visible in the original frames, but have been lost a bit along the top edge during stacking, however they are still nicely visible along the bottom edge.
Cestodiscus peplum Brun, 1891. Original description: Brun, J. (1891). Diatomées espèces nouvelles marines, fossiles ou pélagiques. Mémoires de la Société de Physique et d’Histoire Naturelle de Genève, 31(part 2, no.1): 1-47, pl. 11-22. Plate 19, Figure 5.
For another example of C. peplum on this site, and some more background to it, see here.