viii CONTENTS 



PAGE 



2. INTER-RELATIONS BETWEEN THE LARGER GROUPS (FAMILIES, 



SERIES, AND CLASSES) ....... 62 



3. DESCRIPTION OF CHANGES ACTUALLY OBSERVED AND THE 

 PROBABLE CAUSES OF SAME (' PAL^ONTOLOGICAL LAW 

 OF EVOLUTION') 65 



SECTION II. 



THE EXPLANATORY DOMAIN OF THE HYPOTHESIS OF 

 EVOLUTION. 



CHAPTER I. 

 INTRODUCTION ......... 77 



CHAPTER II. 



LIMITATION OF THE EXPLANATORY DOMAIN OF THE EVOLUTIONARY 



HYPOTHESIS. 



PRELIMINARY OBSERVATION 83 



1. WE ARE NOT JUSTIFIED IN REGARDING THE ORIGIN OF 

 ORGANISMS UPON OUR EARTH AS THE RESULT OF AN 



EVOLUTIONARY PROCESS 84 



2. WE ARE NOT JUSTIFIED IN BRINGING ANIMALS AND PLANTS 



INTO GENETIC CONNECTION ...... 108 



3. WE ARE NOT JUSTIFIED, IN THE PRESENT STATE OF OUR KNOW- 

 LEDGE, IN BRINGING THE FAMILIES AND CLASSES OF THE 

 ANIMAL AND PLANT WORLDS INTO GENETIC CONNECTION . 117 

 APPENDIX : ARE THERE ' HIGHER ' AND ' LOWER ' TYPES ? . 139 



SECTION III. 

 EVOLUTIONARY HYPOTHESES. 



CHAPTER I. 



THE PRINCIPAL ATTEMPTS AT EXPLANATION HITHERTO. 



1. LAMARCKISM AND NEO-LAMARCKISM ..... 145 

 2. DARWINISM AND NEO-DARWINISM . . . . .157 



