Opinions from W. D. Matthew 1918
- 'Aelurodon hyaenoides is recombined as Brachypsalis hyaenoides'
- 'Amblycastor belongs to Eutypomyidae'
- 'Amblycastor fluminis belongs to Amblycastor'
- 'Amphicyon amnicola is recombined as Pliocyon amnicola'
- 'Aphelops fossiger is recombined as Teleoceras fossiger'
- 'Aphelops fossiger is recombined as Teleoceras fossiger' according to Osborn 1898
- 'Aphelops planiceps is recombined as Teleoceras planiceps'
- 'Borocyon is a nomen dubium'
- 'Borocyon robustum is a nomen dubium'
- 'Borophagus is a nomen dubium'
- 'Borophagus diversidens is a nomen dubium'
- 'Brachypsalis modicus belongs to Brachypsalis'
- 'Canis gregarius is recombined as Pseudocynodictis gregarius'
- 'Canis gregarius is recombined as Pseudocynodictis gregarius' according to Schlosser 1902
- 'Canis gregarius is recombined as Cynodictis gregarius' according to Schlaikjer 1935
- 'Canis vafer is recombined as Leptocyon vafer'
- 'Canis vafer is recombined as Vulpes vafer' according to Macdonald 1948
- 'Cervavus sinclairi belongs to Cervavus'
- 'Cranioceras belongs to Dromomerycidae'
- 'Cranioceras unicornis belongs to Cranioceras'
- 'Dibelodon is a subjective synonym of Gompotherium'
- 'Dibelodon belongs to ' according to Cope 1884
- 'Hesperocyon belongs to Canidae' according to Scott 1890
- 'Hesperocyon is a nomen nudum'
- 'Hypohippus pertinax belongs to Hypohippus'
- 'Leptocyon belongs to Canidae'
- 'Mastodon (Tetralophodon) mirificus is recombined as Stegomastodon mirificus'
- 'Mastodon (Tetralophodon) mirificus is recombined as Stegomastodon mirificus' according to Pohlig 1912
- 'Mastodon brevidens is recombined as Zygolophodon brevidens'
- 'Mastodon brevidens belongs to Mastodon' according to Cope 1889
- 'Mastodon serridens is recombined as Zygolophodon serridens'
- 'Mastodon serridens belongs to Mastodon' according to Cope 1884
- 'Mastodon shepardii is a nomen dubium'
- 'Merychyus (Metoreodon) was reranked as Metoreodon and belongs to Oreodontidae'
- 'Peraceras superciliosus belongs to Peraceras'
- 'Peraceras troxelli belongs to Peraceras'
- 'Pliocyon belongs to Amphicyonidae'
- 'Pliocyon medius belongs to Pliocyon'
- 'Proamphicyon is a subjective synonym of Daphoenus'
- 'Proamphicyon belongs to ' according to Hatcher 1902
- 'Promastodon is a nomen nudum'
- 'Promastodon belongs to ' according to Pohlig 1912
- 'Rhabdobunus is a subjective synonym of Stegomastodon'
- 'Rhinoceros crassus is recombined as Aphelops crassus'
- 'Rhinoceros crassus is recombined as Aphelops crassus' according to Osborn 1890
- 'Rhinoceros meridianus is recombined as Aphelops meridianus'
- 'Rhinoceros meridianus is recombined as Aphelops meridianus' according to Dumble 1894
- 'Tephrocyon confertus belongs to Tephrocyon'
- 'Tetrabelodon is a subjective synonym of Gomphotherium'
- 'Tetrabelodon belongs to ' according to Cope 1884
- 'Trilophodon is a subjective synonym of Gomphotherium'
- 'Trilophodon belongs to ' according to Falconer 1857