x ii ILLUSTRATIONS 



Figure Page 



1. Table showing stratigraphic sequence 7 



2. Ceratopsia localities 11 



3. Phylogeny of the Ceratopsia 28 



4. Skull of Monoclonius (Centrosaurus) flexus, lateral view 31 



5. Skull of Monoclonius (Centrosaurus) flexus, palatal view 36 



6. Hyoid of Triceratops serratus 38 



7. Cervicals I, II, III of Monoclonius (Centrosaurus) flexus 39 



8. Cervicals V and VI of Monoclonius (Centrosaurus) flexus 41 



9. Cervical IX of Monoclonius (Centrosaurus) flexus 42 



10. Dorsal II of Monoclonius (Centrosaurus) flexus 42 



11. Cervical IX of Monoclonius (Centrosaurus) nasicornus 43 



12. Dorsal II of Monoclonius (Centrosaurus) nasicornus 43 



13. Dorsal VI of Monoclonius (Centrosaurus) flexus 43 



14. Dorsal IX of Monoclonius (Centrosaurus) flexus 44 



15. Dorsal IX of Monoclonius (Centrosaurus) nasicornus 45 



16. Dorsal XI of Monoclonius (Centrosaurus) flexus 46 



1 7. Sacrum and ilia of Monoclonius (Centrosaurus) flexus, dorsal view 47 



18. Sacrum and ilia of Monoclonius (Centrosaurus) flexus, ventral view 49 



19. Scapula and coracoid of Monoclonius (Centrosaurus) flexus 50 



20. Sternals of Monoclonius (Centrosaurus) flexus 52 



21. Humerus of Monoclonius (Centrosaurus) flexus 53 



22. Ulna of Monoclonius (Centrosaurus) flexus 54 



23. Radius of Monoclonius (Centrosaurus) flexus 55 



24. Fore foot, anterior view of Monoclonius (Centrosaurus) flexus 56 



25. Fore foot, lateral view of Monoclonius (Centrosaurus) flexus 56 



26. Pubis and ischium of Monoclonius (Centrosaurus) flexus 58 



27. Femur of Monoclonius (Centrosaurus) flexus 59 



28. Tibia and fibula of Monoclonius (Centrosaurus) flexus 61 



29. Hind foot, anterior view of Monoclonius (Centrosaurus) flexus 62 



30. Skull of Chasmosaurus belli, palatal view 67 



31. Skull of Triceratops, sagittal section, showing brain cavity 72 



32. Skull of Protoceratops andrewsi, lateral view 75 



33. Skull of Protoceratops andrewsi, dorsal view 77 



34. Anterior cervicals of Protoceratops 80 



35. Anterior cervicals of Leptoceratops 80 



36. Pubis of Protoceratops 80 



37. Pubis of Leptoceratops 80 



38. Skull of Chasmosaurus kaiseni, lateral view 95 



39. Skull of P entaceratops sternbergii, lateral view 109 



40. Skeleton of P entaceratops fenestratus, lateral view 1 12 



41. Skull of Triceratops obtusus, lateral view 126 



42. Squamosal of Torosaurus latus, ventral view 131 



