Aulacodiscus kittonii (and var. africanus), in an arrangement of 4 diatoms. It looks like there should be a fifth, but I couldn’t find it anywhere on the slide. From Monterey Bay, and the Congo River. It’s labelled as ‘Dancer, Manchester’, but this could have just been resold by him. The style of the slide is similar to Barbour Bros. and also WA Firth. Olympus BHB microscope using 450nm LED light. 40x Leitz Pl Apo NA 1.00 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).
Aulacodiscus kittonii Arnott ex Ralfs in Pritchard 1861. Published in: Pritchard, A. (1861). A history of infusoria, including the Desmidiaceae and Diatomaceae, British and foreign. Fourth edition enlarged and revised by J. T. Arlidge, M.B., B.A. Lond.; W. Archer, Esq.; J. Ralfs, M.R.C.S.L.; W. C. Williamson, Esq., F.R.S., and the author. pp. [1]-xii, [1]-968, 40 pls [I-XV]. London: Whittaker and Co.. Page 844, Plate 8, Figure 24.
Aulacodiscus kittonii var. africana (Cottam) Rattray 1888. Spelt africanus on the slide. Published in: Rattray, J. (1888). A revision of the genus Aulacodiscus Ehrb. Journal of the Royal Microscopical Society 8(3): 337-382, 3 pls [V-VII]. Page 376. This name is currently regarded as a synonym of Aulacodiscus africanus Cottam.
The var. Africana are the 3 around the edge.