CONTENTS. 



Centres of Creation— Means of Dispersal by Changes of Climate and of the Level 

 of the Land, and by Occasional Means— Dispersal during the Glacial Period- 

 Alternate Glacial Periods in the North and South . . . page 322 



CHAPTER XII. 



GEOGllAnilC'AL DISTRIBUTION' COUtinUcJ. 



Distribution of Fresh-water Productions— On the Inhabitants of Oceanic Islands- 

 Absence of Batrachians and of Terrestrial Mammals— On the Relation of the In- 

 habitants of Islands to those of the nearest Main-land— On Colonization from the 

 nearest Source with subsequent Modification— Summary of the last and present 

 Chapter 351 



CHAPTER XIII. 



MUTUAL AFFINITIES OF ORGANIC BEINGS : MORPHOLOGY : EMBRYOLOGY : RUDI- 

 MENTARY ORGANS. 



Classiflcation, Groups subordinate to Groups— Natural System— Eules and Difficulties 

 in Classification, explained on the Theory of Descent with Modification— Classi- 

 fication of Varieties- Descent always used in Classification— Analogical or Adap- 

 tive Characters— Affinities, General, Complex, and Radiating— Extinction sepa- 

 rates and defines Groups— Morphology, between members of the same Class, be- 

 tween parts of the same Individual— Embryology, Laws of, explained by Varia- 

 tions not supervening at an early Age, and being inherited at a corresponding 

 Age— Rudimentary Organs ; their Origin explained— Summary . . 372 



CHAPTER XIV. 



RECAPITULATION AND CONCLUSION. 



Recapitulation of the Objections to the Theory of Natural Selection— Recapitulation 

 of the General and Special Circumstances in its favor — Causes of the General 

 Belief in the Immutability of Species— IIow far the Theory of Natural Selection 

 may be extended- Efl"ects of its Adoption on the Study of Natural History— Con- 

 cluding Remarks ......... 412 



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Instruction to Binder.— The Diagram to front page 114. 



