A strew slide from Mt Hillaby, Barbados. Mounted in Styrax and dated 20/1/1920. Yellowed mountant. A busy slide with a lot of different diatom species present. No makers name. Olympus BHB microscope using 450nm LED light. As well as the wider field of view of the strew, I imaged a couple of the diatoms using the 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. Images stacked in Zerene (Pmax).
Both diatoms I imaged are I think Cestodiscus sp. The larger one is viewed from below with the rim upwards towards the coverslip. The smaller one was viewed with the rim downwards.
Cestodiscus pulchellus is mentioned for Barbados in JH Robinson, The Occurrence and Distribution of the Diatoms in the Oceanic Beds of Barbados II (Clarke’s Cliff), The Journal of the Barbados Museum and Historical Society, 1936, IV(1), 9-11, JH Robinson, The Occurrence and Distribution of the Diatoms in the Oceanic Beds of Barbados III and IV (Spring Gully, Sedge Pond), The Journal of the Barbados Museum and Historical Society, 1937, 4(4), 180-183 and JH Robinson, The Occurrence and Distribution of the Diatoms in the Oceanic Beds of Barbados V (Joe’s River), The Journal of the Barbados Museum and Historical Society, 1938, 5(3), 144-150. Cestodiscus pulchellus Greville 1866. Published in: Greville, R.K. (1866). Descriptions of new and rare Diatoms. Series XX. Transactions of the Microscopical Society, New Series, London 14: 121-130, pls XI, XII. Page 123, Plate XI, Figure 5.
However these two do not look to be the same species, and I could well believe there are multiple Cestodiscus sp. for Barbados. So I will leave them simply as Cestodiscus sp. for now.
For another example of a slide by this maker see here.