Opinions from R. Owen 1840
- 'Enaliosauri is corrected as Enaliosauria and belongs to Reptilia'
- 'Ichthyosaurus belongs to Enaliosauria'
- 'Ichthyosaurus acutirostris belongs to Ichthyosaurus'
- 'Ichthyosaurus cheiroligostinus is a subjective synonym of Ichthyosaurus platyodon'
- 'Ichthyosaurus chirostrongulostinus is a subjective synonym of Ichthyosaurus tenuirostris'
- 'Ichthyosaurus communis belongs to Ichthyosaurus'
- 'Ichthyosaurus giganteus is a subjective synonym of Ichthyosaurus platyodon'
- 'Ichthyosaurus grandipes is a subjective synonym of Ichthyosaurus tenuirostris'
- 'Ichthyosaurus intermedius belongs to Ichthyosaurus'
- 'Ichthyosaurus latifrons belongs to Ichthyosaurus'
- 'Ichthyosaurus latimanus belongs to Ichthyosaurus'
- 'Ichthyosaurus lonchiodon belongs to Ichthyosaurus'
- 'Ichthyosaurus platyodon belongs to Ichthyosaurus'
- 'Ichthyosaurus tenuirostris belongs to Ichthyosaurus'
- 'Ichthyosaurus thyreospondylus belongs to Ichthyosaurus'
- 'Ichthyosaurus trigonus belongs to Ichthyosaurus'
- 'Plesiosaurus belongs to Enaliosauri'
- 'Plesiosaurus affinis belongs to Plesiosaurus'
- 'Plesiosaurus arcuatus belongs to Plesiosaurus'
- 'Plesiosaurus brachyspondylus belongs to Plesiosaurus'
- 'Plesiosaurus costatus belongs to Plesiosaurus'
- 'Plesiosaurus doedicomus belongs to Plesiosaurus'
- 'Plesiosaurus dolichodeirus belongs to Plesiosaurus'
- 'Plesiosaurus giganteus is a subjective synonym of Plesiosaurus brachyspondylus'
- 'Plesiosaurus giganteus belongs to Plesiosaurus' according to Conybeare 1824
- 'Plesiosaurus grandis belongs to Plesiosaurus'
- 'Plesiosaurus hawkinsii belongs to Plesiosaurus'
- 'Plesiosaurus macrocephalus belongs to Plesiosaurus'
- 'Plesiosaurus macromus belongs to Plesiosaurus'
- 'Plesiosaurus pachyomus belongs to Plesiosaurus'
- 'Plesiosaurus recentior is a subjective synonym of Plesiosaurus brachyspondylus'
- 'Plesiosaurus rugosus belongs to Plesiosaurus'
- 'Plesiosaurus subtrigonus belongs to Plesiosaurus'
- 'Plesiosaurus trigonus belongs to Plesiosaurus'
- 'Plesiosaurus trigonus belongs to Plesiosaurus' according to Cuvier 1824
- 'Plesiosaurus trochanterius belongs to Plesiosaurus'
- 'Proteosaurus is a subjective synonym of Ichthyosaurus'