Opinions from H. F. Osborn 1908
- 'Brontotherium hatcheri belongs to Brontotherium'
- 'Diplacodon belongs to Diplacodontinae'
- 'Dolichorhinus intermedius belongs to Dolichorhinus'
- 'Lambdotherium brownianum is recombined as Eotitanops brownianus'
- 'Limnohyops matthewi belongs to Limnohyops'
- 'Limnohyops monoconus belongs to Limnohyops'
- 'Limnohyops priscus belongs to Limnohyops'
- 'Manteoceras belongs to Manteoceratinae'
- 'Manteoceras washakiensis belongs to Manteoceras'
- 'Mesatirhinus belongs to Brontotheridae'
- 'Mesatirhinus petersoni belongs to Mesatirhinus'
- 'Metarhinus belongs to Brontotheridae'
- 'Metarhinus earlei belongs to Metarhinus'
- 'Metarhinus fluviatilis belongs to Metarhinus'
- 'Palaeosyops borealis is recombined as Eotitanops borealis'
- 'Palaeosyops borealis is recombined as Eotitanops borealis' according to Osborn 1907
- 'Palaeosyops borealis belongs to Palaeosyops' according to Wallace 1980
- 'Palaeosyops borealis is recombined as Titanops borealis' according to Peterson 1914
- 'Palaeosyops borealis is recombined as Telmatotherium borealis' according to Osborn 1897
- 'Palaeosyops copei belongs to Palaeosyops'
- 'Palaeosyops grangeri belongs to Palaeosyops'
- 'Palaeosyops hyognathus is recombined as Dolichorhinus hyognathus'
- 'Palaeosyops hyognathus is recombined as Dolichorhinus hyognathus' according to Hatcher 1895
- 'Palaeosyops hyognathus belongs to Palaeosyops' according to Osborn 1889
- 'Palaeosyops leidyi belongs to Palaeosyops'
- 'Palaeosyops megarhinus is recombined as Mesatirhinus megarhinus'
- 'Palaeosyops ultimus is a nomen nudum'
- 'Palaeosyops ultimus belongs to Palaeosyops' according to Matthew 1897
- 'Protitanotherium belongs to Manteoceratinae'
- 'Protitanotherium superbum belongs to Protitanotherium'
- 'Ptolemaia lyonsi belongs to Ptolemaia'
- 'Symborodon copei belongs to Symborodon'
- 'Telmatherium altidens belongs to Telmatherium'
- 'Telmatherium ultimum belongs to Telmatherium'
- 'Telmatotherium cornutum is a subjective synonym of Dolichorhinus hyognathus'
- 'Telmatotherium diploconum is recombined as Metarhinus diploconus'