Opinions from E. T. Newton 1891
- 'Balaena belongs to Balaenidae'
- 'Balaena affinis belongs to Balaena'
- 'Balaena balaenopsis is recombined as Balaena (Balaenula) balaenopsis'
- 'Balaena biscayensis belongs to Balaena'
- 'Balaena definata is recombined as Balaenoptera definita'
- 'Balaena emarginata is recombined as Balaenoptera emarginata'
- 'Balaena primigenius [misspelled as Balaena primigenia] belongs to Balaena'
- 'Balaenodon belongs to Physeteridae'
- 'Balaenodon physaloides belongs to Balaenodon'
- 'Balaenoptera belongs to Balaenidae'
- 'Balaenoptera borealina belongs to Balaenoptera'
- 'Balaenotus was reranked as Balaena (Balaenotus) and belongs to Balaena'
- 'Balaenotus insignis is recombined as Balaena (Balaenotus) insignis'
- 'Balanadae is corrected as Balaenidae and belongs to Cetacea'
- 'Belemnoziphius compressus is recombined as Mesoplodon compressus'
- 'Burtinopsis was reranked as Megaptera (Burtinopsis) and belongs to Megaptera'
- 'Burtinopsis minutus is recombined as Megaptera (Burtinopsis) minuta'
- 'Burtinopsis similis is recombined as Megaptera (Burtinopsis) similis'
- 'Canis primigenius is a nomen dubium'
- 'Cetotherium belongs to Balaenidae'
- 'Cetotherium brevifrons is recombined as Cetotherium (Heterocetus) brevifrons'
- 'Cetotherium dubium is recombined as Cetotherium (Plesiocetus) dubium'
- 'Choneziphius belongs to Physeteridae'
- 'Choneziphius packardi belongs to Choneziphius'
- 'Delphinapterus belongs to Delphinidae'
- 'Delphinidae belongs to Cetacea'
- 'Delphinus (Phocaena) uncidens is recombined as Globicephalus uncidens'
- 'Delphinus delphis belongs to Delphinus'
- 'Delphinus leucas is recombined as Delphinapterus leucas'
- 'Erignathus was reranked as Phoca (Erignathus) and belongs to Phoca'
- 'Eucetus belongs to Physeteridae'
- 'Eucetus amblyodon belongs to Eucetus'
- 'Globicephala [misspelled as Globicephalus] belongs to Delphinidae'
- 'Halitherium belongs to Sirenia'
- 'Halitherium canhami belongs to Halitherium'
- 'Herpetocetus belongs to Balaenidae'
- 'Herpetocetus scaldiensis belongs to Herpetocetus'
- 'Heterocetus was reranked as Cetotherium (Heterocetus) and belongs to Cetotherium'
- 'Homaeocetus [misspelled as Homocetus] belongs to Physeteridae'
- 'Hoplocetus belongs to Physeteridae'
- 'Hoplocetus borgerhoutensis belongs to Hoplocetus'
- 'Hoplocetus crassidens belongs to Hoplocetus'
- 'Hoplocetus curvidens belongs to Hoplocetus'
- 'Hyperoodon belongs to Physeteridae'
- 'Megaptera belongs to Balaenidae'
- 'Megaptera affinis belongs to Megaptera'
- 'Mesoplodon belongs to Physeteridae'
- 'Mesoplodon floweri is corrected as Mesoplodon floris and belongs to Mesoplodon'
- 'Mesoplodon scaphoides belongs to Mesoplodon'
- 'Monodon belongs to Delphinidae'
- 'Monodon monoceros belongs to Monodon'
- 'Orca belongs to Delphinidae'
- 'Orca citoniensis belongs to Orca'
- 'Orca gladiator belongs to Orca'
- 'Palaeodelphis is a subjective synonym of Physodon'
- 'Palaeodelphis fusiformis is recombined as Physodon fusiformis'
- 'Palaeodelphis grandis is recombined as Physodon grandis'
- 'Phoca belongs to Carnivora'
- 'Phoca barbata is recombined as Phoca (Erignathus) barbata'
- 'Phoca moori belongs to Phoca'
- 'Phocaena belongs to Delphinidae'
- 'Phocaena communis belongs to Phocaena'
- 'Phocaena crassidens is recombined as Pseudorca crassidens'
- 'Phocanella belongs to Carnivora'
- 'Phocanella minor belongs to Phocanella'
- 'Physeter belongs to Physeteridae'
- 'Physeter macrocephalus belongs to Physeter'
- 'Physeteridae belongs to Cetacea'
- 'Physeterula belongs to Physeteridae'
- 'Physeterula dubusii belongs to Physeterula'
- 'Physodon belongs to Physeteridae'
- 'Plesiocetus was reranked as Cetotherium (Plesiocetus) and belongs to Cetotherium'
- 'Plesiocetus brialmonti is recombined as Cetotherium (Plesiocetus) brialmonti'
- 'Plesiocetus garopii is recombined as Balaenoptera (Plesiocetus) goropi'
- 'Plesiocetus hupschii is recombined as Cetotherium (Plesiocetus) hupschi'
- 'Pseudorca belongs to Delphinidae'
- 'Solarium spiratum is recombined as Philippia spirata'
- 'Squalodon belongs to Squalodontidae'
- 'Squalodon antverpiensis is corrected as Squalodon antwerpiensis and belongs to Squalodon'
- 'Squalodontidae belongs to Cetacea'
- 'Trichechus belongs to Carnivora'
- 'Trichecodon huxleyi is recombined as Trichechus huxleyi'
- 'Tursiops tursio belongs to Tursiops'
- 'Ziphius angulatus is recombined as Mesoplodon angulatus'
- 'Ziphius angustus is recombined as Mesoplodon angustus'
- 'Ziphius gibbus is recombined as Mesoplodon gibbus'
- 'Ziphius longirostris is recombined as Mesoplodon longirostris'
- 'Ziphius planirostris is recombined as Choneziphius planirostris'
- 'Ziphius planus is recombined as Choneziphius planus'
- 'Ziphius tenuirostris is recombined as Mesoplodon tenuirostris'