CONTENTS 



Class Chondrichthyes 160 



Class Osteichthyes 160 

 Crossopterygians, Dipnoans, and the Origin of the Superclass Tetrapoda 163 



Class Amphibia 166 



Class Reptilia 167 



Class Aves 171 



Class Mammalia 172 

 References 177 



Chapter Twelve: The History of the Primates 178 



Classification of the Primates 178 



Tree Shrews 178 



Lemurs 179 



Tarsiers 179 



Monkeys 179 



The Anthropoid Apes 179 



Summary of Classification 181 

 Prosimians in the Fossil Record 181 

 Apes in the Fossil Record 183 



Parapithecus and Propliopithecus 183 



Proconsul 184 



Dryopithecines 184 



Oreopithecus 184 



The Australopithecines 185 

 Man in the Fossil Record 188 



Pithecanthropus 188 



The Heidelberg Jaw 191 



The Piltdown Fraud 191 



The Swanscombe Sktdl 192 



The Steinheim and Galley Hill Skulls 192 



'Neanderthal Man 192 



Cro-Magnon Man 196 

 Interpretations of the Fossil Record 196 

 References 198 



PART THREE: THE ORIGIN OF VARIATION 

 ("Descent Vi'iih Modification") 199 



Chapter Thirteen: Gene Mutation 201 



Elementary Mendelian Concepts 201 



The Mendelian Laws 201 



Sex Linkage 204 



Quantitative Inheritance 205 

 The Gene Theory 206 



Gene 'Number and Gene Size 206 



Mutation in Nature 207 



Rate of Mutation 208 



Direction of Mutation 208 



Experimental Production of Mutation 209 

 Geographic Subspecies and Neo-Darwinian Evolution 209 

 References 213 



Chapter Fourteen: Chromosomal Mutations 214 



Longitudinal Differentiation of the Chromosomes 214 

 Specificity of Synapsis 214 

 The Salivary Gland Chromosomes 215 



xiv 



