Entogonia sp. (probably E. jeremiana) from Conset, Barbados. Single example on the slide. Prepared by JA Long. 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. 46 images stacked in Zerene (Pmax).
As mentioned above I think this is Probably Entogonia jeremiana. There is a good review of this genus in: Holmes, R.W. & Brigger, A.L. (1979). The marine fossil diatom genus Entogonia Greville – A review. Bacillaria 2: 155-214. This one is shown in Plate 8, Figure 73. Entogonia Jeremiana Bergon 1892, Schmidt’s Atlas Plate 203, Figure 3. Original description: Bergon, P. (1892). Monographie du genre Entogonia (fin). II. Classification et description des espèces. Le Diatomiste, 1(10): 128-147, pls. II-IV. Page 140, Plate 1 Figure 7, Plate 3 Figure 14.