Opinions from J. R. Ellerman and T. C. S. Morrisson-Scott 1951
- 'Balaena belongs to Balaenidae'
- 'Balaenoptera belongs to Balaenopteridae'
- 'Balaenopteridae belongs to Mysticeti'
- 'Balanadae is corrected as Balaenidae and belongs to Mysticeti'
- 'Berardius belongs to Ziphiidae'
- 'Delphinapterinae belongs to Monodontidae'
- 'Delphinapterus belongs to Delphinapterinae'
- 'Delphinidae belongs to Odontoceti'
- 'Delphinus belongs to Delphinidae'
- 'Delphinus (Grampus) was reranked as Grampus and belongs to Delphinidae'
- 'Eschrichtiidae belongs to Mysticeti'
- 'Eubalaena belongs to Balaenidae'
- 'Globicephala belongs to Delphinidae'
- 'Hyperoodon belongs to Ziphiidae'
- 'Iniinae belongs to Platanistidae'
- 'Kogia belongs to Kogiinae'
- 'Kogiinae belongs to Physeteridae'
- 'Lagenorhynchus belongs to Delphinidae'
- 'Lipotes belongs to Iniinae'
- 'Lissodelphis belongs to Delphinidae'
- 'Megaptera belongs to Balaenopteridae'
- 'Megaptera (Eschrichtius) was reranked as Eschrichtius and belongs to Eschrichtiidae'
- 'Mesoplodon belongs to Ziphiidae'
- 'Mesoplodon gervaisi is a subjective synonym of Mesoplodon europaeus'
- 'Monodon belongs to Monodontinae'
- 'Monodontidae belongs to Odontoceti'
- 'Monodontinae belongs to Monodontidae'
- 'Neomeris belongs to Phocaenidae'
- 'Odontoceti belongs to Cetacea'
- 'Orca (Orcaella) was reranked as Orcaella and belongs to Delphinidae'
- 'Orcinus belongs to Delphinidae'
- 'Phocaena belongs to Phocaenidae'
- 'Phocaenina was reranked as the family Phocaenidae and belongs to Odontoceti'
- 'Physeter belongs to Physeterinae'
- 'Physeteridae belongs to Odontoceti'
- 'Physeterinae belongs to Physeteridae'
- 'Platanista belongs to Platanistinae'
- 'Platanistina was reranked as the family Platanistidae and belongs to Odontoceti'
- 'Platanistinae belongs to Platanistidae'
- 'Pseudorca belongs to Delphinidae'
- 'Sotalia belongs to Delphinidae'
- 'Steno belongs to Delphinidae'
- 'Steno (Stenella) was reranked as Stenella and belongs to Delphinidae'
- 'Tursiops belongs to Delphinidae'
- 'Ziphiidae belongs to Ziphioidea'
- 'Ziphius belongs to Ziphiidae'