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the former Order NOTASPIDEA  P. Fischer, 1883 was splitted:
Class:  Gastropoda  Cuvier, 1797
Subclass:  Heterobranchia  J.E. Gray, 1840
Infraclass:  Euthyneura  Spengel, 1881
Subterclass:  Tectipleura  Schrödl, Jörger, Klussmann-Kolb & Wilson, 2011
Order:  Umbraculida  Odhner, 1939
Superfamily:  Umbraculoidea  Dall, 1889 (1827)
Family:  Umbraculidae  Dall, 1889

Umbraculum umbraculum

Class:  Gastropoda  Cuvier, 1797
Subclass:  Heterobranchia  J.E. Gray, 1840
Infraclass:  Euthyneura  Spengel, 1881
Superorder:  Nudipleura  Wägele & Willan, 2000
Order:  Pleurobranchida  J.E. Gray, 1827
Superfamily:  Pleurobranchoidea  J.E. Gray, 1827
Family:  Pleurobranchidae  J.E. Gray, 1827
Subfamily:  Pleurobranchinae  J.E. Gray, 1827

Berthellina edwardsii	Berthellina granulata	Berthellina utris	Pleurobranchus areolatus	Pleurobranchus nigropunctatus
Pleurobranchus reticulatus

Subfamily:  Pleurobranchaeinae Pilsbry, 1896

Pleurobranchaea bubala

Pleurobranchaea tarda