PART II
Sec.Sec. iv. and v. On the evidence from Geology. (The reasons for combining the two sections are given in the Introduction) 22
Sec. vi. Geographical distribution 29
Sec. vii. Affinities and classification 35
Sec. viii. Unity of type in the great classes 38
Sec. ix. Abortive organs 45
Sec. x. Recapitulation and conclusion 48
ESSAY OF 1844
PART I
CHAPTER I 57-80
ON THE VARIATION OF ORGANIC BEINGS UNDER DOMESTICATION; AND ON THE PRINCIPLES OF SELECTION.
Variation On the hereditary tendency Causes of Variation On Selection Crossing Breeds Whether our domestic races have descended from one or more wild stocks Limits to Variation in degree and kind In what consists Domestication--Summary
CHAPTER II 81-111
ON THE VARIATION OF ORGANIC BEINGS IN A WILD STATE; ON THE NATURAL MEANS OF SELECTION; AND ON THE COMPARISON OF DOMESTIC RACES AND TRUE SPECIES.
Variation Natural means of Selection Differences between "Races" and "Species":-first, in their trueness or variability Difference between "Races" and "Species" in fertility when crossed Causes of Sterility in Hybrids Infertility from causes distinct from hybridisation Points of Resemblance between "Races" and "Species" External characters of Hybrids and Mongrels Summary Limits of Variation