Opinions from R. Kellogg 1931
- 'Allodesmidae belongs to Pinnipedia'
- 'Allodesmus belongs to Allodesmidae'
- 'Aulocetus is an objective synonym of Cetotheriopsis'
- 'Aulophyseter belongs to Physeteridae'
- 'Balaena cuvierii is recombined as Balaenoptera cuvieri'
- 'Balaenodon lintianus is recombined as Cetotheriopsis lintianus'
- 'Cetotheriomorphus is a nomen dubium'
- 'Cetotheriomorphus dubius is a nomen dubium'
- 'Cetotherium (Cetotheriophanes) is a nomen dubium'
- 'Cetotherium (Plesiocetopsis) was reranked as Plesiocetopsis and belongs to Cetotheriidae'
- 'Cetotherium brevifrons is recombined as Heterocetus brevifrons'
- 'Cetotherium helmersenii is recombined as Cetotherium (Eucetotherium) helmersenii'
- 'Grypolithax belongs to Delphinidae'
- 'Grypolithax obscura belongs to Grypolithax'
- 'Grypolithax pavida belongs to Grypolithax'
- 'Heterocetus belongs to Cetotheriidae'
- 'Idiocetus belongs to Balaenopteridae'
- 'Lamprolithax belongs to Delphinidae'
- 'Lamprolithax annectens belongs to Lamprolithax'
- 'Lamprolithax simulans belongs to Lamprolithax'
- 'Liolithax belongs to Delphinidae'
- 'Liolithax kernensis belongs to Liolithax'
- 'Loxolithax belongs to Delphinidae'
- 'Loxolithax sinuosa belongs to Loxolithax'
- 'Nannolithax belongs to Delphinidae'
- 'Nannolithax gracilis belongs to Nannolithax'
- 'Neotherium belongs to Allodesmidae'
- 'Neotherium mirum belongs to Neotherium'
- 'Oedolithax belongs to Delphinidae'
- 'Oedolithax mira belongs to Oedolithax'
- 'Palaeobalaena belongs to Cetotheriidae'
- 'Palaeobalaena bergi belongs to Palaeobalaena'
- 'Parietobalaena belongs to Cetotheriidae'
- 'Parietobalaena securis belongs to Parietobalaena'
- 'Peripolocetus belongs to Mysticeti'
- 'Peripolocetus vexillifer belongs to Peripolocetus'
- 'Pinnipedia was reranked as a order and belongs to Mammalia'
- 'Platylithax belongs to Delphinidae'
- 'Platylithax robusta belongs to Platylithax'
- 'Plesiocetus garopii belongs to Plesiocetus'
- 'Plesiocetus hupschii belongs to Plesiocetus'
- 'Squalodon belongs to Squalodontidae'
- 'Squalodon errabundus belongs to Squalodon'
- 'Stenodon is replaced by Cetotheriopsis'
- 'Tiphyocetus belongs to Cetotheriidae'
- 'Tiphyocetus temblorensis belongs to Tiphyocetus'