• Ditylum J.W. Bailey ex L.W. Bailey, 1861
• Ditylum brightwellii (T.West) Grunow, 1885 (uncertain > unassessed)
• Ditylum brightwellii f. biangulata Hustedt, 1930 (uncertain > unassessed)
• Ditylum brightwellii f. pentagona Gaarder, 1951 (uncertain > unassessed)
• Ditylum brightwellii f. tetragona (Grunow in Van Heurck) Hustedt, 1930 accepted as Ditylum brightwellii var. tetragona Grunow in Van Heurck, 1883
• Ditylum brightwellii var. brightwellii Peragallo & Peragallo, 1901 (uncertain > unassessed)
• Ditylum brightwellii var. inaequalis Grunow in Van Heurck, 1883 (uncertain > unassessed)
• Ditylum brightwellii var. pyramidalis H.Ferrando, 1964 (uncertain)
• Ditylum brightwellii var. tetragona Grunow in Van Heurck, 1883 (uncertain > unassessed)
• Ditylum brightwellii var. trigona Grunow in Van Heurck, 1883 (uncertain > unassessed)
• Ditylum buchananii von Stosch, 1987 (uncertain > unassessed)
• Ditylum cornutum Forti & Schulz, 1932 (uncertain > unassessed)
• Ditylum ehrenbergii Grunow in Van Heurck, 1883 (uncertain > unassessed)
• Ditylum grovei Brun, 1891 (uncertain > unassessed)
• Ditylum inaequale J.W.Bailey ex L.W.Bailey, 1862 (uncertain > unassessed)
• Ditylum intricatum Grunow accepted as Triceratium intricatum T.West, 1860
• Ditylum pernodi Schröder, 1906 (uncertain > unassessed)
• Ditylum segmentale Brun, 1891 (uncertain > unassessed)
• Ditylum sol (Grunow) De Toni, 1894 (uncertain > unassessed)
• Ditylum sol Cleve, 1900 accepted as Triceratium sol A. Schmidt, 1890
• Ditylum trigonum L.W.Bailey ex L.W.Bailey, 1862 (uncertain > unassessed)
• Ditylum trigonum Schroder, 1906 (uncertain > unassessed)
• Ditylum trigonum Schröder, 1906 (uncertain > unassessed)
• Ditylum undulatum Mann, 1907 accepted as Triceratium undulatum Brightwell, 1858