[ref. ID; 2013]
Body shape ovoid, some species elongate. Body ciliature complete, sometimes with paired cilia, in many longitudinal kineties. There is always a frange of membranelles beneath, but extending only to the left of, the oral aperture. The number of membranelles in the frange varies but there are at least 3 and usually more. The anterior part of the kinety immediately to the right of the oral aperture may be modified to become a highly vibratile double row of cilia forming the paroral ciliature. The frange of membranelles always interrupts the left kineties so that they continue forwards past the frange to the suture line. This feature distinguishes it from the genera Furgasonia and Enigmostoma where the membranelles occur in the suture line area and thus do not interrupt the kineties. The cytopharynx is supported by a basket of trichites. There is a single contractile vacuole situated in the middle of the body. Macronucleus with adjacent micronucleus centrally positioned.
Quote; Colin R. Curds "British and other freshwater ciliated protozoa Part I Ciliophora: Kinetofragminophora" Cambridge University Press, 1982 (ref. ID; 2013)

• Nassula ambigua Stein, 1854 (ref. ID; 1622)
• Nassula ambigua var. tumida Maskell
  See; Nassula tumida Maskell, 1887 (ref. ID; 1622)
• Nassula aurea Ehrenberg, 1833 (ref. ID; 1308, 1622, 2245, 4611, 4613) reported year? (ref. ID; 1618, 4678)
  See; Obertrumia aurea (ref. ID; 4611, 4613)
• Nassula brunnea Fabre-Domergue, 1885 (ref. ID; 1622)
• Nassula carpathica Lepsi, 1927 (ref. ID; 1622)
• Nassula citrea (ref. ID; 191, 1622)
• Nassula elegans Ehrenberg, 1833 (ref. ID; 1622, 2245, 4611) reported year? (ref. ID; 3690)
  See; Nassulopsis elegans (ref. ID; 4611)
  Syn; Nassula versicolor Andre, 1916 (ref. ID; 1622)
• Nassula exigua Kahl, 1931 (ref. ID; 3593) reported author and year? (ref. ID; 1622)
• Nassula flava Claparede & Lachmann, 1858 (ref. ID; 1622)
• Nassula graciis Claparede & Lachmann (ref. ID; 3342)
• Nassula gracilis Kahl (ref. ID; 1219, 1335, 1622)
  Syn; Nassula elegans Blochmann-Roux (ref. ID; 1622)
• Nassula gutturata Gajevskaja, 1927 (ref. ID; 1622)
• Nassula hesperidea Entz, 1884 (ref. ID; 1622)
• Nassula heterovesiculata Gelei, 1939
  See; Synhymenia heterovesiculata
• Nassula labiata Kahl, 1933 (ref. ID; 1620)
• Nassula longinassa Foissner (ref. ID; 3698)
• Nassula magna Smith, 1897 (ref. ID; 1622)
• Nassula microstoma Calkins, 1903(?) or Cohn, 1866
  See; Placus socialis (ref. ID; 1619, 1622, 3540)
• Nassula minima Minkewitsch (ref. ID; 3698)
• Nassula muscicola (ref. ID; 1622)
• Nassula notata (O. F. Muller) Hamburger & V. Buddbr., 1911 (ref. ID; 1622)
  Syn; Nassula microstoma Cohn, 1866 (ref. ID; 1622); Nassula microstoma Entz, 1884 (ref. ID; 1622)
• Nassula ornata Ehrenberg, 1833 (ref. ID; 1622, 1629, 3115, 4488, 4611) reported year? (ref. ID; 3690, 3698) reported author and year? (ref. ID; 3292)
• Nassula ougandae Dragesco, 1972
  See; Enigmostoma ougandae
• Nassula picta Greeff, 1888 (ref. ID; 1622, 1629, 3593, 4488, 4611) reported year? (ref. ID; 3698)
• Nassula pusilla (ref. ID; 1622)
• Nassula rotunda Gelei (ref. ID; 3698)
• Nassula theresae Fabre-Domergue, 1931 (ref. ID; 1622)
• Nassula tumida Maskell, 1887 (ref. ID; 1622)
  Syn; Nassula ambigua var. tumida Maskell (ref. ID; 1622)
• Nassula versicolor Andre, 1916
  See; Nassula elegans (ref. ID; 1622)