Historical Background 1
General Osteology 7
Skull 7
Dermal Skull Roof 8
Dermal Bones of the Palate 15
Ossifications of the Palatoquadrate Cartilage 17
Ossifications of the Braincase 18
Mandible 23
Stapes 25
Dentition 25
Axial Skeleton 26
Ribs 33
Gastralia 34
Appendicular Skeleton 34
Limbs 41
Systematic Review 56
Order Pelycosauria COPE 1878 56
Suborder Caseasauria WILLISTON 1912 57
Family Eothyrididae ROMER and PRICE 1940 58
Eothyris ROMER 1937 58
Oedaleops LANGSTON 1965 59
Family Caseidae WILLISTON 1912 59
Casea WILLISTON 1910b 59
Caseopsis OLSON 1962 60
Cotylorhynchus STOVALL 1937 60
Angelosaurus OLSON and BEERBOWER 1953 61
Ennatosaurus EFREMOV 1956 62
Caseid of Uncertain Position 62
Caseoides OLSON and BEERBOWER 1953 62
Tentatively Assigned to the Caseidae 62
Phreatophasma EFREMOV 1954 62
Suborder Eupelycosauria KEMP 1982 63
Family Varanopseidae ROMER and PRICE 1940 63
Varanops WILLISTON 1914 64
Aerosaurus ROMER 1937 64
Mycterosaurus WILLISTON 1915 65
Varanodon OLSON 1965 65
Tentatively Assigned to the Varanopseidae 66
Basicranodon 66
Ruthiromia 66
Family Ophiacodontidae NOPCSA 1923 66
Archaeothyris REISZ 1972 67
Clepsydrops COPE 1875 67
Stereorhachis GAUDRY 1880 68
Baldwinonus ROMER and PRICE 1940 68
Stereophallodon ROMER 1937 68
Ophiacodon MARSH 1878 69
Family Edaphosauridae COPE 1882 71
Edaphosaurus COPE 1882 71
Family Sphenacodontidae MARSH 1878 74
Subfamily Haptodontinae 74
Haptodus GAUDRY 1886 74
Subfamily Secodontosaurinae 75
Secodontosaurus ROMER 1936 75
Subfamily Sphenacodontinae 76
Macromerion ? schwartzenbergii FRITSCH 1889 76
Neosaurus NOPCSA 1923 76
Bathygnathus LEIDY 1854 76
Sphenacodon MARSH 1878 77
Ctenospondylus ROMER 1936 78
Dimetrodon COPE 1878d 79
Sphenacodontidae Incertae Sedis 82
Pelycosauria Incertae Sedis 82
Colobomycter 82
Delorhynchus 83
Echinerpeton 83
Glaucosaurus 83
Lupeosaurus 83
Milosaurus 84
Nitosaurus 84
Protoclepsydrops 84
Tetraceratops 84
Thrausmosaurus 85
Trichasaurus 85
Xyrospondylus 85
Varanosaurus BROILI 1904 85
Reptilia Tentatively Assigned to the Pelycosauria 86
Anningia 86
Elliotsmithia 86
Forms Incorrectly Assigned to the Pelycosauria 86
Phylogenetic Relationships 87
Geographical and Geological Distribution 94
Literature Cited 97
Index 101