Opinions from H. F. Osborn 1929
- 'Anisacodon montanus is a subjective synonym of Menodus giganteus'
- 'Archidiskodon sonoriensis belongs to Archidiskodon'
- 'Asinus belongs to ' according to Harper 1945
- 'Asinus belongs to ' according to Hopwood 1942
- 'Asinus belongs to ' according to Dollman 1935
- 'Asinus belongs to ' according to Noack 1884
- 'Asinus belongs to ' according to Owen 1846
- 'Asinus belongs to Equidae' according to Gray 1822
- 'Asinus is a subjective synonym of Equus'
- 'Asinus is a subjective synonym of Equus' according to Scott 1895
- 'Asinus was reranked as Equus (Asinus) and belongs to Equus' according to Lydekker 1916
- 'Asinus is a subjective synonym of Equus' according to Pavlow 1890
- 'Asinus is a subjective synonym of Equus' according to Thomas 1884
- 'Asinus is a subjective synonym of Equus' according to Sclater 1884
- 'Asinus is a subjective synonym of Equus' according to von Meyer 1832
- 'Asinus belongs to ' according to Trumler 1961
- 'Asinus belongs to ' according to Mooser 1959
- 'Asinus belongs to ' according to Quinn 1958
- 'Brontops belongs to Brontotheridae'
- 'Brontops dispar belongs to Brontops'
- 'Brontops robustus belongs to Brontops'
- 'Brontops validus is a subjective synonym of Brontops dispar'
- 'Brontotherium ingens is a subjective synonym of Menodus giganteus'
- 'Canis marshii is a nomen dubium'
- 'Diconodon is a subjective synonym of Menodus'
- 'Diploceras is a subjective synonym of Eotitanotherium'
- 'Diploceras osborni is recombined as Eotitanotherium osborni'
- 'Diploclonus belongs to '
- 'Diploclonus amplus belongs to Diploclonus'
- 'Elephas floridanus belongs to Elephas'
- 'Eobasileus uintensis belongs to Eobasileus'
- 'Eotherium is a nomen dubium'
- 'Haplacodon is a nomen dubium'
- 'Helotherium is a subjective synonym of Orohippus'
- 'Helotherium procyoninum is a subjective synonym of Orohippus pumilus'
- 'Heterotitanops is a nomen dubium'
- 'Heterotitanops parvus is a nomen dubium'
- 'Lambdotherium brownianum is recombined as Eotitanops brownianus'
- 'Lambdotherium brownianum is recombined as Eotitanops brownianus' according to Osborn 1913
- 'Lambdotherium primaevum belongs to Lambdotherium'
- 'Lambdotherium primaevum belongs to Lambdotherium' according to Loomis 1907
- 'Leidyotherium is a nomen dubium'
- 'Leidyotherium belongs to ' according to Prout 1860
- 'Leurocephalus is a subjective synonym of Telmatherium'
- 'Leurocephalus is a subjective synonym of Telmatotherium' according to Earle 1895
- 'Leurocephalus is a subjective synonym of Telmatotherium' according to Earle 1892
- 'Leurocephalus cultridens is recombined as Telmatotherium cultridens' according to Earle 1895
- 'Leurocephalus cultridens is recombined as Telmatherium cultridens'
- 'Limnohyops belongs to '
- 'Limnohyus is a subjective synonym of Palaeosyops'
- 'Limnohyus laevidens is recombined as Limnohyops laevidens'
- 'Limnohyus laevidens is a subjective synonym of Palaeosyops laticeps' according to Matthew 1899
- 'Limnohyus laticeps is recombined as Limnohyops laticeps'
- 'Limnohyus laticeps is recombined as Limnohyops laticeps' according to Trouessart 1898
- 'Limnohyus laticeps is recombined as Limnohyops laticeps' according to Roger 1896
- 'Limnohyus laticeps is recombined as Limnohyops laticeps' according to Earle 1892
- 'Limnohyus laticeps is recombined as Palaeosyops laticeps' according to Marsh 1884
- 'Limnohyus laticeps belongs to Limnohyus' according to Cope 1884
- 'Limnohyus laticeps belongs to Limnohyus' according to Osborn and etal 1878
- 'Limnohyus robustus is recombined as Palaeosyops robustus'
- 'Megaceratops is a subjective synonym of Megacerops'
- 'Megaceratops is a subjective synonym of Symborodon' according to Cope 1902
- 'Megaceratops acer is recombined as Megacerops acer'
- 'Megaceratops helocerus is recombined as Menodus heloceras'
- 'Megacerops bicornutus is recombined as Diploclonus bicornutus'
- 'Megacerops brachycephalus is recombined as Brontops brachycephalus'
- 'Megacerops marshi is recombined as Allops marshi'
- 'Megacerops primitivus is recombined as Teleodus primitivus'
- 'Megacerops tyleri is recombined as Diploclonus tyleri'
- 'Menodus angustigenis is a nomen dubium'
- 'Menodus dolichoceras is recombined as Brontotherium dolichoceras'
- 'Menodus peltoceras is a subjective synonym of Brontotherium curtum'
- 'Menodus platyceras is recombined as Brontotherium platyceras'
- 'Menodus selwynianus is recombined as Diploclonus selwynianus'
- 'Menodus syceras is recombined as Megacerops syceras' according to Osborn 1929
- 'Menodus tichoceras is recombined as Brontotherium tichoceras'
- 'Menops is a subjective synonym of Menodus'
- 'Menops varians is recombined as Menodus varians'
- 'Mesatirhinus superior is recombined as Dolichorhinus superior'
- 'Miobasileus is a nomen dubium'
- 'Miobasileus ophryas is a nomen dubium'
- 'Palaeosyops borealis is recombined as Eotitanops borealis'
- 'Palaeosyops borealis is recombined as Eotitanops borealis' according to Osborn 1913
- 'Palaeosyops diaconus is a subjective synonym of Palaeosyops robustus'
- 'Palaeosyops diaconus is recombined as Limnohyops diaconus' according to Trouessart 1898
- 'Palaeosyops diaconus is recombined as Limnohyops diaconus' according to Roger 1896
- 'Palaeosyops diaconus is recombined as Limnohyus diaconus' according to Earle 1891
- 'Palaeosyops diaconus is recombined as Limnohyus diaconus' according to Cope 1884
- 'Palaeosyops fontinalis belongs to Palaeosyops'
- 'Palaeosyops fontinalis belongs to Palaeosyops' according to Matthew 1899
- 'Palaeosyops fontinalis is recombined as Limnohyops fontinalis' according to Hay 1902
- 'Palaeosyops fontinalis is recombined as Limnohyops fontinalis' according to Trouessart 1898
- 'Palaeosyops fontinalis is recombined as Limnohyops fontinalis' according to Roger 1896
- 'Palaeosyops fontinalis is recombined as Limnohyops fontinalis' according to Earle 1892
- 'Palaeosyops fontinalis is recombined as Limnohyus fontinalis' according to Cope 1884
- 'Palaeosyops fontinalis is recombined as Limnohyus fontinalis' according to Cope 1873
- 'Palaeosyops humilis belongs to Palaeosyops' according to Roger 1896
- 'Palaeosyops humilis is recombined as Limnohyus humilis' according to Leidy 1872
- 'Palaeosyops humilis belongs to Palaeosyops' according to Leidy 1872
- 'Palaeosyops humilis is a nomen dubium'
- 'Palaeosyops humilis belongs to Palaeosyops' according to Matthew 1899
- 'Palaeosyops humilis belongs to Palaeosyops' according to Trouessart 1898
- 'Palaeosyops hyognathus is recombined as Dolichorhinus hyognathus'
- 'Palaeosyops junior is recombined as Mesatirhinus junius'
- 'Palaeosyops longirostris belongs to Palaeosyops'
- 'Palaeosyops longirostris is a subjective synonym of Telmatherium megarhinum' according to Matthew 1899
- 'Palaeosyops longirostris belongs to Palaeosyops' according to Earle 1892
- 'Palaeosyops major belongs to Palaeosyops'
- 'Palaeosyops manteoceras is a nomen nudum'
- 'Palaeosyops manteoceras belongs to Palaeosyops' according to Matthew 1899
- 'Palaeosyops megarhinus is recombined as Mesatirhinus megarhinus'
- 'Palaeosyops minor is recombined as Anchippodus minor' according to Leidy 1872
- 'Palaeosyops ultimus is a nomen nudum'
- 'Palaeosyops vallidens is recombined as Dolichorhinus vallidens'
- 'Palaeosyops vallidens is recombined as Manteoceras vallidens' according to Hatcher 1895
- 'Palaeosyops vallidens is recombined as Telmatotherium vallidens' according to Osborn 1895
- 'Palaeotherium giganteum is recombined as Menodus giganteus'
- 'Palaeotherium giganteum belongs to Palaeotherium' according to Pomel 1849
- 'Palaeotherium maximum is a nomen dubium'
- 'Palaeotherium maximum belongs to Palaeotherium' according to Leidy 1852
- 'Palaeotherium proutii is recombined as Menodus proutii'
- 'Palaeotherium proutii is recombined as Menodus proutii' according to Cope 1889
- 'Palaeotherium proutii is recombined as Menodus proutii' according to Cope 1886
- 'Palaeotherium proutii is recombined as Titanotherium proutii' according to Leidy 1852
- 'Protitanotherium belongs to Brontotheridae'
- 'Rhinoceros americanus is a nomen dubium'
- 'Rhinoceros americanus is recombined as Eotherium americanum' according to Leidy 1853
- 'Rhinoceros americanus belongs to Rhinoceros' according to Leidy 1852
- 'Symborodon is a subjective synonym of Menodus'
- 'Symborodon altirostris is a subjective synonym of Megacerops acer'
- 'Symborodon bucco is recombined as Megacerops bucco'
- 'Symborodon copei is recombined as Megacerops copei'
- 'Symborodon hypoceras is recombined as Brontotherium hypoceras'
- 'Symborodon torvus is recombined as Menodus torvus'
- 'Symborodon trigonoceras is recombined as Menodus trigonoceras'
- 'Teleodus belongs to '
- 'Teleodus avus belongs to Teleodus'
- 'Telmatherium incisivum is recombined as Sthenodectes incisivum'
- 'Telmatotherium cornutum is a subjective synonym of Dolichorhinus hyognathus'
- 'Telmatotherium diploconum is recombined as Rhadinorhinus diploconum'
- 'Titanops is a subjective synonym of Brontotherium'
- 'Titanops curtus is recombined as Brontotherium curtum'
- 'Titanops elatus is a subjective synonym of Brontotherium gigas'
- 'Titanops medius is recombined as Brontotherium medium'
- 'Titanotherium is a subjective synonym of Menodus'
- 'Titanotherium is a subjective synonym of Menodus' according to Cope 1889
- 'Titanotherium ramosum is recombined as Brontotherium ramosum'