A strew from Walfish Bay, South Africa (now known as Walvis bay, Namibia) deep sea dredgings. Nice array of species with a clear mountant, and not too dense which made imaging easier. Prepared by Bernard Hartley. Mounted in Aroclor and dated April 1975. Olympus BHB microscope using 450nm LED light. 40x Leitz Pl Apo NA 1.00 objective, oil immersion. Olympus Aplanat Achromat condenser, oil immersion, brightfield lighting. 2.5x Nikon CF PL photoeyepiece. Monochrome converted Nikon d850 camera. Image stacked prepared in Zerene (Pmax). I couldn’t get close enough with the 63x Leitz objective, hence the 40x. This was probably due to the height of the coverslip ring.
I’ve chose three diatoms to image at higher resolution.
Two are Actinocyclus sp. (perhaps Actinocyclus subtilis), once viewed from the underside with the rim facing the coverslip, the other viewed from above.
The other is an Actinoptychus sp. There were a few Actinoptychus on the slide but this one just looked different. I think it is an ‘initial cell’ of an Actinoptychus sp.. There is more about those here.