CONTENTS XV 



PAGE 



91. On the Meaning of the Term " Evolution " . .276 



{a) Emergent Evolution ; {b) Evolution regarded as Change ; 

 {c) Evolution and " Progress." 



92. On Hypotheses of Evolution ...... 279 



//. Animal Affinities 



93. On Homologies ........ 283 



(a) The Criterion of Homology ; (b) Tectonic Characters 

 express Homologies. 



94. On the Primary Animal Homologies .... 284 



(a) The Primary Animal Classification ; (b) The Parallelism 

 of Embryological Phases and Classificatory Groupings. 



95. On Generalized Tectonic Characters .... 286 



(a) The Classification of the Chordata. 



96. On Homologies as Indicative of Affinities . . . 289 



(a) The Conception of Recapitulation. 



97. On the Morphological Method . . . . .292 



(a) Phylogenies. 



///. The Paleontological Records 



98. On the Stratigraphical Series of Rocks .... 295 



{a) Fossilization. 



99. On the Nature and Limitations of Paleontological Evidence 298 



{a) Paleontological sequences ; {b) Phylogenetic Histories. 



IV. The Evolutionary Career 

 ICQ. On the Origin of Life ....... 302 



loi. On the Earliest Forms of Life ..... 302 



(rt) The Original, Terrestrial, Physical Conditions ; {b) The 

 Original Modes of Metabolism. 



102. On ''Lines of Descent". ...... 305 



103. On the Main Features of the Evolutionary Career . .309 



{a) The Materialization of Life ; {b) Structural Manifestations 

 of Life. 



104. On the Main Types of Life . . . . . .311 



105. On the Deployments of Living Things . . . .316 



106. On the Episodes of Evolution. . . . . .317 



107. On the Future of the Evolutionary Career . . .318 

 (<?) The Time-Scale and Physical Conditions ; {b) Man. 



Index .......... 



322 



