Family UNDELLIDAE Kofoid & Campbell, 1929

Lorica goblet-shaped, occasionally elongate and sometimes with suboral ledge; an inner collar may be present; wall trilayered; all forms marine (eupelagic); no fossil species.

[Some genera should be combined? See Balech (1975).]

Amplectella Kofoid & Campbell, 1929. Several species.
Amplectellopsis Kofoid & Campbell, 1929. Few species.
Cricundella Kofoid & Campbell, 1929 (syn. Circundella). Few species.
Micrundella Busch, 1949. Few species.
Proplectella Kofoid & Campbell, 1929 (syn. Proplecta). Many species.
Undella Daday, 1887. Many species.
Undellopsis Kofoid & Campbell, 1929. Many species.
Incertae sedis:
Rotundocylis Kufferath, 1952. Single species.