• Undella Daday, 1887
• Undella aculeata Jörgensen, 1924 accepted as Parundella aculeata (Jörgensen, 1924)
• Undella angustior Jörgensen, 1924 accepted as Undella claparedei var. angustior Jörgensen, 1924 accepted as Proplectella angustior (Jörgensen, 1924)
• Undella armata Brandt, 1906 accepted as Xystonellopsis armata Brandt, 1906
• Undella attenuata Jörgensen, 1924
• Undella azorica Cleve, 1899 accepted as Favella azorica (Cleve, 1899) Jörgensen, 1924
• Undella biangulata Kofoid & Campbell, 1929
• Undella californiensis Kofoid & Campbell, 1929
• Undella campanula Schmidt, 1902 accepted as Favella campanula (Schmidt, 1902) Jörgensen, 1924
• Undella caudata Jörgensen, 1924 accepted as Parundella caudata (Ostenfeld, 1899) Jörgensen, 1924
• Undella claparedei (Entz) Daday, 1887 accepted as Proplectella claparedei (Entz, 1885)
• Undella claparedei f. ovata Jörgensen, 1924 accepted as Proplectella ovata (Jörgensen, 1924)
• Undella claparedei var. angustior Jörgensen, 1924 accepted as Proplectella angustior (Jörgensen, 1924)
• Undella claparedei var. globosa Brandt, 1906 accepted as Proplectella globosa (Brandt, 1906) emended Kofoid & Campbell, 1929
• Undella clevei Jörgensen, 1924
• Undella collaria Brandt, 1906 accepted as Amplectella collaria (Brandt) Kofoid & Campbell, 1929
• Undella dilatata Kofoid & Campbell, 1929
• Undella filigera Laackmann, 1910 accepted as Albatrossiella filigera (Laackmann, 1910) Kofoid & Campbell, 1929
• Undella globosa Brandt, 1906 accepted as Proplectella globosa (Brandt, 1906) emended Kofoid & Campbell, 1929
• Undella hadai Balech, 1962
• Undella heros Cleve, 1899 accepted as Xystonellopsis heros (Cleve) Kofoid & Campbell, 1929
• Undella heros var. dahli Brandt, 1906 accepted as Xystonellopsis dahli (Brandt, 1906) Kofoid & Campbell, 1929
• Undella heros var. gaussi Laackmann, 1909 accepted as Xystonellopsis gaussi (Laackmann, 1910) Kofoid & Campbell, 1929
• Undella hyalina Daday, 1887
• Undella hyalina f. attenuata accepted as Undella attenuata Jörgensen, 1924
• Undella lachmanni Daday, 1887 accepted as Parundella lachmanni (Daday, 1887)
• Undella lachmanni Daday, 1887
• Undella lohmanni Jörgensen, 1924 accepted as Parundella lohmanni (Joergensen, 1924) Kofoid & Campbell, 1929
• Undella marsupialis Brandt, 1906 accepted as Undellopsis marsupialis (Brandt, 1906) Kofoid & Campbell, 1929
• Undella marsupialis f. subangulata Jörgensen, 1924 accepted as Undellopsis subangulata (Jörgensen) Kofoid & Campbell
• Undella messinensis Brandt, 1906 accepted as Parundella messinensis (Brandt, 1906)
• Undella monocollaria Laackmann, 1910 accepted as Amplectella monocollaria (Laackmann, 1910) Kofoid & Campbell, 1929
• Undella ostenfeldi Kofoid & Campbell, 1929
• Undella paradoxa Cleve, 1899 accepted as Xystonellopsis paradoxa (Cleve, 1899) Jörgensen, 1924
• Undella pellucida Jørgensen, 1900 accepted as Parundella pellucida (Jörgensen, 1900)
• Undella pentagona (Jörgensen) Kofoid & Campbell, 1929 accepted as Proplectella pentagona (Jörgensen, 1924)
• Undella perpusilla (Kofoid & Campbell, 1929) Balech, 1975 accepted as Proplectella perpusilla Kofoid & Campbell, 1929
• Undella pistillum Kofoid & Campbell, 1929
• Undella subacuta Cleve, 1900 accepted as Proplectella subacuta (Cleve, 1900) Kofoid & Campbell, 1929
• Undella subacuta f. acuta accepted as Proplectella acuta (Jörgensen, 1924)
• Undella subacuta var. pentagona Jörgensen, 1924 accepted as Proplectella pentagona (Jörgensen, 1924)
• Undella subacuta var. subcaudata Jörgensen, 1924 accepted as Proplectella subcaudata (Jörgensen, 1924)
• Undella subcaudata Jörgensen, 1924 accepted as Proplectella subcaudata (Jörgensen, 1924)
• Undella subcaudata subsp. acuta (Jörgensen, 1924) Balech, 1975
• Undella tenuirostris Brandt, 1906 accepted as Xystonellopsis tenuirostris Brandt, 1906
• Undella tenuirostris var. brandti Laackmann, 1910 accepted as Xystonellopsis brandti (Laackmann) Jörgensen, 1924
• Undella tenuirostris var. brandti Laackmann, 1910 accepted as Xystonellopsis brandti (Laackmann) Jörgensen, 1924
• Undella tricollaria Laackmann, 1910 accepted as Amplectella tricollaria (Laackmann, 1910) Balech, 1975
• Undella turgida Kofoid & Campbell, 1929
• Undellaria Cooper & Grant, 1975 †