CONTENTS. 



Additions and Cokrections, to the Sixth Edition . . Page ix 



Historical Sketch xiii 



Introduction .. .. ...•.««,„. 1 



CHAPTER I. 



Variation under Domestication. 



Causes of Variability — Effects of Habit and the use or disuse of 

 Parts — Correlated Variation — Inheritance — Character of 

 Domestic Varieties — Difficulty of distinguishing between 

 Varieties and Species — Origin of domestic varieties from one or 

 more species — Domestic Pigeons, their Differences and Origin — 

 Principles of Selection, anciently followed, their Effects — 

 Methodical and Unconscious Selection — Unknown Origin of our 

 Domestic Productions — Circumstances favourable to Man's 

 power of Selection .. .. .. .. e . .. .. ., 7 



CHAPTER IL 



Variation under Nature. 



Variability — Individual differences — Doubtful species — Wide 

 ranging, much diffused, and common species, vary most — 

 Species of the larger genera in each country vary more fre- 

 quently than the species of the smaller genera — Many of the 

 species of the larger genera resemble varieties in being very 

 closely, but unequally, related to each other, and in having 

 restricted ranges 51 



