Evolution Of Mammalian Molar TeethPDF电子书下载

INTRODUCTION 1

CLASSIFICATION OF THE MAMMALIA ADOPTED IN THIS BOOK 11

CHAPTER Ⅰ．THE TRANSITION FROM THE REPTILIAN TO THE MOST PRIMITIVE MAMMALIAN TEETH 18

1．The Upper Triassic Mammals Dromatherium and Microcondon 18

2．A new classification of the Mesozoic Mammals 21

3．Illustrations of the chief Triconodonta and Trituberculata 24

4．The origin of the tritubercular type sought in 1888 among the Mesozoic Mammalia 31

CHAPTER Ⅱ．FIRST OUTLINE OF TRITUBERCULAR EVOLUTION IN MAMMALS 36

CHAPTER Ⅲ．TRITUBERCULY IN RELATION TO THE HUMAN MOLAR TEETH AND THE PRIMATES 48

1．Ontogenetic development of the teeth 48

2．＂The history of the cusps of the human molar teeth＂ 55

The concresence theory 57

Mechanical relations of the upper and lower teeth 60

Evidence that the upper human molars were triangular 62

CHAPTER Ⅳ．TRITUBERCULY IN ITS APPLICATION TO THE MOLAR TEETH OF THE UNGULATES OR HOOFED MAMMALS．COMPLETION OF THE NOMENCLATURE 66

1．Disadvantages of previous systems of nomenclature of the molar cusps 66

2．Methods of analysis of molar elements．Nomenclature of the molars of Ungulates 66

3．Application of the theory of trituberculy to the Perissodactyla 72

The horse molar 72

The rhinoceros molar 72

CHAPTER Ⅴ．TRITUBERCULY：A REVIEW DEDICATED TO THE LATE PROFESSOR COPE 74

Polybuny 74

Comparison of nomenclatures 76

Tritubercular homologies 77

The early stages of sexituberculy 80

Lower molars 80

The nomenclature of the molar cusps and crests 82

The evolution of the Ungulate molar 83

CHAPTER Ⅵ．CHRONOLOGICAL OR GEOLOGICAL SUCCESSION OF MOLAR TYPES 91

1．Reptilian Ancestors of Mammals in the Trias 91

2．The Triassic Mammals 94

3．Mammals of the Jurassic 94

4．Upper Cretaceous Mammals 95

5．Basal Eocene Mammals 98

6．Lower Eocene Mammals 98

Résumé of Geological Succession of Types 99

CHAPTER Ⅶ．THE ORIGINAL OR PRIMITIVE STRUCTURE OF THE MOLAR TEETH IN THE DIFFERENT ORDERS OF MAMMALS 100

The major classification of the Mammalia 100

Protodonta 101

Allotheria or Multituberculata 101

Monotremata 105

Marsupialia 108

Molar teeth of Multituberculates，Marsupials(？)，and Placentals in the Upper Cretaceous 115

Insectivora 117

Cheiroptera 129

Carnivora 131

Evolution of carnasial teeth in Creodonta and Fissipedia 135

Convergence of upper carnassials in Creodonta and Fissipedia 138

Fissipedia 142

Rodentia 144

Simplicidentata 145

Duplicidentata 148

Tillodontia 151

Superorder Ungulata 163

Amblypoda 164

Condylarthra 168

Artiodactyla 171

Perissodactyla 174

Chalicotheroidea or Ancylopoda 184

Hyracoidea 185

Proboscidea 186

Sirenia 188

South American Ungulates 189

Cetacea 190

Zeuglodontia 191

CHAPTER Ⅷ．EVOLUTION OF THE PREMOLARS 193

Premolars in primitive Mammals 193

Adaptation of premolars 194

Various upper premolar types 194

Cusp addition in the premolars 195

Superior premolars 195

Inferior premolars 198

CHAPTER Ⅸ．OBJECTIONS AND DIFFICULTIES，AND OTHER THEORIES 201

Ⅰ．That the tritubercular type is not primitive 201

1．The plexodont or progressive simplification theory of Ameghino 201

2．Objections by Fleischmann and Mahn answered by Scott 204

3．The primitive polybuny theory 205

Ⅱ．That the Cope-Osborn theory of the origin of the superior molars in incorrect 208

1．Cusp homologies founded on embryogeny 208

Order of embryonic cusp-development in Insectivora 210

Summary of Woodward＇s conclusion 212

Ontogenetic order according to Marett Tims 213

The premolar analogy theory 215

Palaeontological difficulties in the premolar analogy theory 217

Gidley＇s restudy(1906)of Jurassic-Mammals supports embryogeny and the premolar analogy theory 219

Addendum：the＂trituberculy＂of Zalambdodonts a secondary acquirement or＂pseudo-trituberculy＂ 225

Conclusion 227

CHAPTER Ⅹ．RECTIGRADATIONS IN THE TEETH 229

Homoplasy as a law of latent or potential homology 229

Homology 237

Lankester＇s reply to the preceding article 238

BIBLIOGRAPHY 240