CONTENTS 



Additions and Corrections, to the Sixth Edition . 



Historical Sketch 



Ihtboduotion 



FACE 

 . 1 

 . 11 



. 25 



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 — 

 DiflBculty of distinguishing between Varieties and Species — Origin of 

 Domestic Varieties from one or more Species — Domestic Pigeons, 

 their Differences and Origin — Principles of Selection ancienlly fol- 

 lowed, their Effects — Methodical and Unconscious Selection — Un- 

 known Origin of our Domestic Productions — Circumstances favora- 

 ble to Man's power of Selection 



31 



CHAPTER II 



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 frequently 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 



(3) 



u 



