CONTENTS. 
Introduction 
Page 1 
CHAPTEE L 
Variation under Domestication. 
Causes of Variability—Effects of Habit — Correlation of Growth — 
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 — Principle of Selection anciently followed, 
its Effects — Methodical and Unconscious Selection — Unknown 
Origin of our Domestic Productions — Circumstances favourable 
to Man’s power of Selection. 7-43 
CHAPTEE IL 
Variation under Nature. 
Variability — Individual differences — Doubtful species — Wide 
ranging, much diffused, and common species vary most—Spe¬ 
cies of the larger genera in any country vary more 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 .. .. 44-59 
