[Class] Polycystinea Ehrenberg, 1838 - polycystines see Superclass Polycystinia Ehrenberg, 1838
   Order Nassellaria Ehrenberg, 1875 see Class Nassellaria Ehrenberg, 1847
     Family Theoperidae Haeckel, 1881
       Genus Eucyrtidium Ehrenberg, 1847
         01 Eucyrtidium acuminatum (Ehrenberg, 1844)
         02 †Eucyrtidium aderces Nigrini & Caulet, 1992
         03 †Eucyrtidium anniae Caulet, 1986
         04 Eucyrtidium annulatum (Popofsky, 1913)
         05 Eucyrtidium anomalum (Haeckel, 1860)
         06 †Eucyrtidium antiquum Caulet, 1991
         07 †Eucyrtidium asanoi Sakai, 1980
         08 †Eucyrtidium biconicum (Vinassa de Regny, 1900)
         09 Eucyrtidium calvertense Martin, 1904
         10 †Eucyrtidium cheni Takemura, 1992
         11 †Eucyrtidium cienkowskii Haeckel, 1887
         12 †Eucyrtidium diaphanes Sanfilippo, 1973
         13 Eucyrtidium dictyopodium (Haeckel, 1887)
         14 †Eucyrtidium dufresni Caulet, 1979
         15 Eucyrtidium erythromystax Nigrini & Caulet, 1992
         16 †Eucyrtidium heptacolum (Haeckel, 1887)
         17 †Eucyrtidium hexacolum (Haeckel, 1887)
         18 Eucyrtidium hexagonatum Haeckel, 1887
         19 Eucyrtidium hexastichum Haeckel, 1887
         20 †Eucyrtidium indiensis Caulet, 1979
         21 †Eucyrtidium inflatum Kling, 1973
         22 †Eucyrtidium infundibulum (Haeckel, 1887)
         23 †Eucyrtidium mariae Caulet, 1991
         24 †Eucyrtidium matuyamai Hays, 1970
         25 †Eucyrtidium montiparum Ehrenberg, 1873
         26 †Eucyrtidium octocolum (Haeckel, 1887)
         27 †Eucyrtidium pseudoinflatum Weaver, 1983
         28 †Eucyrtidium punctatum (Ehrenberg, 1844)
         29 †Eucyrtidium saccoi (Vinassa de Regny, 1900)
         30 †Eucyrtidium spinosum Haeckel, 1887
         31 Eucyrtidium teuscheri Haeckel, 1887
         32 †Eucyrtidium yatsuoense Nakaseko, 1955