CONTENTS: 
CHAPTER I.—INTRODUCTION. 
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Small Areas of Distribution for Species of Hawaiian Snails......... 
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Selection not Always the Cause of Divergence ..............----.---- 
In Many Cases Sexual Selection not the Cause................... 
In Many of the Same Cases Natural Selection not the Cause........ 
May not the Prevention of Free Crossing be an Explanation............ 
Investigation of Causes and Effects of Segregation.......+..........-- 
Segregation the Unifying Principle in Evolution..................... 
CHAPTER II.—Brionomic LAws. 
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SCOMCIOMELOMOMIM CS Hasty ya tea Tats ae asa tiaye Coes als red ven le veleyera\trfe tele, ays 
Why we Commence with the Method of Evolution................ 
Neediotinvestication ofallehactors: . 4298. sees ss aoe cles =. 
Natural and Sexual Selection not the Only Factors............... 
Comparison of Conditions in Natural Species and in Domestic Varie- 
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Amalgamation of Races............. ESE VA sre aM nt Sasha, coe Coe T A oilsas exe se 
Influence of Acquired Characters on Racial Characters............ 
CHAPTER III].—THE EVOLUTION OF NATURAL SPECIES. 
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Divergence Through Variation under Isolation and Unity Through 
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Diversity of Natural Selection not a Sufficient Explanation........ 
Divergence through Independent Transformation................ 
. Natural Selection as Explanation of Evolution...................---- 
What Natural Selection does not Explain....................... 
Selection, how Far Determined by External Nature.............. 
MISCAMEMMIMIUY OF SOGCIES se. sca) 5 ec. se nes ee es ee se tees Vb wR lye oe 
CHAPTER IV.—DIVERGENCE UNDER THE SAME ENVIRONMENT. 
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foal 
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aT 
SIN DPW AN HW 
23-29 
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