ILLUSTRATIONS 



Figure Pa S e 



1. Map of the major merycoidodont localities 14 



2. Chart of phylogeny and geological sequence 25 



3. Third and fourth premolars of Protoreodon, Oreonetes, and Merycoidodon 26 



4. Third and fourth premolars of Limnenetes, Eporeodon, Mesoreodon, Promerycochcerus, Merycochoe- 



rus } and Pronomotherium "' 



5. Third and fourth premolars of Merycoides, Phenacocoslus, Ticholeftus, and Metoreodon 28 



6. Third and fourth premolars of Merychyus and Leptauchenia 28 



7. Evolution of the basioccipital region in earlier merycoidodonts 29 



8. Skull and jaw of Protoreodon ?nedius (HT) J-> 



9. Skull and jaw of Protoreodon minor (PLT) 35 



10. Left superior dentition of Protoreodon minor (HT) 35 



11. Left superior dentition of Protoreodon paradoxicus (HT) 36 



12. Left superior dentition of Protoreodon parvus (PT) 36 



13. Skull and jaw of Protoreodon pitmilus (PT) 38 



14. Left half, inferior view of skull of Protoreodo?i pumilus (PT) 38 



15. Superior view of mandibular ramus of Protoreodon fumilus (PT) 38 



16. Dentition of Hyomeryx breviceps (GHT) 40 



17. Maxillary fragment of Hyomeryx ■ bt eviceps (GHT) 40 



18. Left mandibular fragment of Bathygenys alpha (GHT) 42 



19. Right mandibular fragment of Bathygenys alpha (PT) 42 



20. Superior dentition of Bathygenys alpha (PLT) 42 



21. Fragments of maxillary and ramus of Merycoidodon culbertsonii (GCT) 48 



22. Left superior dentition of Merycoidodon culbertsonii 49 



23. Hyoid bones of Merycoidodon culbertsonii 50 



24. Skull of Merycoidodon macrorhinus (HT) 58 



25. Skull of Merycoidodon platycephalus (HT) 59 



26. Right half, superior view of skull of Merycoidodon platycephalus (HT) 60 



27. Right half, inferior view of skull of Merycoidodon platycephalus (HT) 60 



28. Skull of Eporeodon bullatus (PLT) 65 



29. Right half, inferior view of skull of Eporeodon bullatus (PLT) 66 



30. Right half, superior view of skull of Eporeodon bullatus (PLT) 66 



31. Skull of Eporeodon condoni (HT) 67 



32. Right half, superior view of skull of Eporeodon condoni (HT) 67 



33. Right half, inferior view of skull of Eporeodon condoni (HT) 67 



34. Skull and jaw of Eporeodon dickinsonensis (HT) 68 



35. Skull and jaw of Eporeodon longifrons perbullatus (HT) 73 



36. Left half, inferior view of skull of Eporeodon longifrons perbullatus (HT) 73 



37. Left half, superior view of skull of Eporeodon longifrons perbullatus (HT) 73 



38. Fragmentary skull of Eporeodon major hybrid us (HT) 78 



39. Skull and superior dentition of Eporeodon major relictus (HT) 79 



40. Skull and jaw of Eporeodon montanus (HT) 80 



41. Skull of Eporeodon occidentalis (GHT) 82 



42. Right half, inferior view of skull of Eporeodon occidentalis (GHT) 82 



43. Right half, superior view of skull of Eporeodon occidentalis (GHT) 82 



44. Skull and jaw of Eporeodon parvus (HT) 85 



