Opinions from R. S. Lull 1933
- 'Anchiceratops belongs to Ceratopsidae'
- 'Anchiceratops longirostris belongs to Anchiceratops'
- 'Anchiceratops ornatus belongs to Anchiceratops'
- 'Arrhinoceratops belongs to Ceratopsidae'
- 'Arrhinoceratops brachyops belongs to Arrhinoceratops'
- 'Bison alticornis is a nomen dubium'
- 'Brachyceratops belongs to Ceratopsidae'
- 'Brachyceratops montanensis belongs to Brachyceratops'
- 'Centrosaurus belongs to Ceratopsidae'
- 'Centrosaurus apertus belongs to Centrosaurus'
- 'Ceratops belongs to Ceratopsidae'
- 'Ceratops montanus belongs to Ceratops'
- 'Ceratopsia belongs to Ornithischia'
- 'Chasmosaurus belongs to Ceratopsidae'
- 'Chasmosaurus brevirostris belongs to Chasmosaurus'
- 'Chasmosaurus kaiseni belongs to Chasmosaurus'
- 'Diceratops hatcheri is recombined as Triceratops hatcheri'
- 'Eoceratops belongs to Ceratopsidae'
- 'Leptoceratops belongs to Protoceratopsidae'
- 'Leptoceratops gracilis belongs to Leptoceratops'
- 'Monoclonius belongs to Ceratopsidae'
- 'Monoclonius canadensis is recombined as Eoceratops canadensis'
- 'Monoclonius crassus belongs to Monoclonius'
- 'Monoclonius cutleri is recombined as Centrosaurus cutleri'
- 'Monoclonius dawsoni belongs to Monoclonius'
- 'Monoclonius flexus is recombined as Centrosaurus flexus'
- 'Monoclonius nasicornus is recombined as Centrosaurus nasicornus'
- 'Monoclonius recurvicornis belongs to Monoclonius'
- 'Monoclonius sphenocerus belongs to Monoclonius'
- 'Notoceratops bonarelli belongs to Notoceratops'
- 'Pentaceratops belongs to Ceratopsidae'
- 'Pentaceratops fenestratus belongs to Pentaceratops'
- 'Pentaceratops sternbergii belongs to Pentaceratops'
- 'Protoceratops belongs to Protoceratopsidae'
- 'Protoceratops andrewsi belongs to Protoceratops'
- 'Protoceratopsidae belongs to Ceratopsia'
- 'Styracosaurus belongs to Ceratopsidae'
- 'Styracosaurus albertensis belongs to Styracosaurus'
- 'Styracosaurus ovatus belongs to Styracosaurus'
- 'Tetrapodosaurus belongs to Ceratopsia'
- 'Tetrapodosaurus borealis belongs to Tetrapodosaurus'
- 'Torosaurus belongs to Ceratopsidae'
- 'Torosaurus gladius belongs to Torosaurus'
- 'Torosaurus latus belongs to Torosaurus'
- 'Triceratops belongs to Ceratopsidae'
- 'Triceratops brevicornus belongs to Triceratops'
- 'Triceratops calicornis belongs to Triceratops'
- 'Triceratops elatus belongs to Triceratops'
- 'Triceratops flabellatus belongs to Triceratops'
- 'Triceratops galeus is a nomen dubium'
- 'Triceratops maximus is a nomen dubium'
- 'Triceratops obtusus belongs to Triceratops'
- 'Triceratops prorsus belongs to Triceratops'
- 'Triceratops serratus belongs to Triceratops'
- 'Triceratops sulcatus is a nomen dubium'