Cestodiscus pulchellus var. trinitatis (Grunow in Van Heurck) F.W. Mills, 1933 accepted as Cestodiscus trinitatis Grunow in Van Heurck, 1883 † (new combination reference)
Coscinodiscus aequalis Grove & Sturt according to Mills, 1933 (original description)
Coscinodiscus argus var. oamaruensis Grove Collection according to Mills, 1933 (original description)
Coscinodiscus dichromus (Brun) Mills, 1896 (new combination reference)
Coscinodiscus dubiosus var. florescens (Grunow in Rattray) Mills, 1933 accepted as Coscinodiscus florescens Grunow in Rattray, 1890 (new combination reference)
Coscinodiscus elegans var. inermis (Pantocsek) Fricke in A. Schmidt, 1902 accepted as Stephanodiscus kanitzii f. inermis Pantocsek, 1886 (new combination reference)
Coscinodiscus hexas (Ehrenberg) F.W. Mills, 1933 accepted as Symbolophora hexas Ehrenberg, 1844 (new combination reference)
Coscinodiscus lineatus var. polychorda (Gran; Peragallo & Peragallo) F.W. Mills, 1933 accepted as Coscinodiscus polychordus Gran, 1897 (new combination reference)
Coscinodiscus mecasmus 'Ehrenberg' according to Mills, 1933 (original description)
Coscinodiscus microtrias (Ehrenberg) Mills, 1933 accepted as Symbolophora microtrias Ehrenberg, 1844 (new combination reference)
Coscinodiscus nobilis var. regius (Grunow) Mills accepted as Coscinodiscus regius 'Grunow', 1878 (new combination reference)
Coscinodiscus ornatus (Rattray) Mills, 1933 accepted as Actinocyclus ornatus Rattray, 1890 (new combination reference)
Coscinodiscus parvulus var. nebulosa Grove Collection according to Mills (original description)
Coscinodiscus pulchellus var. hirtulus (Grunow in Van Heurck) F.W. Mills, 1933 accepted as Cestodiscus hirtulus Grunow in Van Heurck, 1883 † (new combination reference)
Coscinodiscus pulchellus var. trinitatis (Grunow in Van Heurck) F.W. Mills, 1933 accepted as Cestodiscus trinitatis Grunow in Van Heurck, 1883 † (new combination reference)
Coscinodiscus pyxidicula 'Ehrenberg' according to Mills, 1933 (original description)
Coscinodiscus radiatus var. subfasciculata Grove collection according to Mills, 1933 (original description)
Coscinodiscus stellaris 'Ehrenberg' according to Mills, 1933 (original description)
Craspedodiscus subtilis 'Ehrenberg Mikr. p. 12' according to Mills, 1933 (original description)
Cyclotella cantalense (Héribaud) Mills, 1933 accepted as Cymbella cantalense Héribaud, 1908 (new combination reference)
Cyclotella comta var. evidenterpunctata Mayer according to Mills, 1933 (original description)
Cyclotella comta var. notata 'Héribaud' according to Mills (original description)
Cyclotella comta var. perforata Héribaud F.W. Mills, 1933 accepted as Cyclotella perforata Héribaud, 1903 (new combination reference)
Cyclotella grossestriata var. grossestriata 'Otto Müller' according to Mills, 1933, 1905 (original description)