Opinions from F. B. Loomis 1924
- 'Brachymeryx is a subjective synonym of Cyclopidius'
- 'Brachymeryx belongs to ' according to Cope 1878
- 'Brachymeryx feliceps is a subjective synonym of Cyclopidius simus'
- 'Oreodontoides is a subjective synonym of Merychyus'
- 'Eporeodon (Oreodontoides) oregonensis is recombined as Merychyus oregonensis'
- 'Eporeodon relictus belongs to Eporeodon'
- 'Merychyus (Metoreodon) profectus is recombined as Ticholeptus profectus'
- 'Merychyus (Metoreodon) relictus belongs to Merychyus (Metoreodon)'
- 'Merychyus (Metoreodon) relictus belongs to Merychyus (Metoreodon)' according to Matthew 1918
- 'Merychyus curtus belongs to Merychyus'
- 'Merychyus delicatus belongs to Merychyus'
- 'Merychyus paniensis belongs to Merychyus'
- 'Merychyus siouxensis belongs to Merychyus'
- 'Merycochoerus magnus belongs to Merycochoerus'
- 'Merycochoerus matthewi belongs to Merycochoerus'
- 'Merycoides belongs to Merycoidodontidae'
- 'Merycoidodon culbertsonii is recombined as Oreodon culbertsoni' according to Zittel and Schlosser 1923
- 'Merycoidodon culbertsonii is recombined as Oreodon culbertsoni' according to O'Harra 1920
- 'Merycoidodon culbertsonii is recombined as Oreodon culbertsoni' according to Barbour and Cook 1917
- 'Merycoidodon culbertsonii is recombined as Oreodon culbertsoni' according to Moodie 1915
- 'Merycoidodon culbertsonii is recombined as Oreodon culbertsoni' according to Zittel and Schlosser 1911
- 'Merycoidodon culbertsonii is recombined as Oreodon culbertsoni' according to Weber 1904
- 'Merycoidodon culbertsonii is recombined as Oreodon culbertsoni' according to Stewart 1897
- 'Merycoidodon culbertsonii belongs to Merycoidodon'
- 'Merycoidodon culbertsonii belongs to Merycoidodon' according to Thorpe 1923
- 'Merycoidodon culbertsonii belongs to Merycoidodon' according to Thorpe 1921
- 'Merycoidodon culbertsonii belongs to Merycoidodon' according to Scott 1913
- 'Merycoidodon culbertsonii belongs to Merycoidodon' according to Stromer 1912
- 'Merycoidodon culbertsonii belongs to Merycoidodon' according to Osborn 1910
- 'Mesoreodon laticeps belongs to Mesoreodon'
- 'Mesoreodon latidens is recombined as Merycoides latidens'
- 'Mesoreodon longiceps is recombined as Merycoides longiceps'
- 'Oreonetes belongs to Merycoidodontidae'
- 'Promerycochoerus gregoryi belongs to Promerycochoerus'
- 'Promerycochoerus pygmyus belongs to Promerycochoerus'
- 'Promerycochoerus thomsoni belongs to Promerycochoerus'
- 'Ticholeptus hypsodus belongs to Ticholeptus'