Chapter VI

ON THE GEOGRAPHICAL DISTRIBUTION OF ORGANIC BEINGS IN PAST AND PRESENT TIMES.

SECTION FIRST 151-174

Distribution of the inhabitants in the different continents
Relation of range in genera and species
Distribution of the inhabitants in the same continent
Insular Faunas
Alpine Floras
Cause of the similarity in the floras of some distant mountains
Whether the same species has been created more than once
On the number of species, and of the classes to which they belong
in different regions

SECOND SECTION 174-182

Geographical distribution of extinct organisms
Changes in geographical distribution
Summary on the distribution of living and extinct organic beings

SECTION THIRD 183-197

An attempt to explain the foregoing laws of geographical
distribution, on the theory of allied species having a
common descent
Improbability of finding fossil forms intermediate between
existing species

CHAPTER VII 198-213

ON THE NATURE OF THE AFFINITIES AND CLASSIFICATION OF ORGANIC BEINGS.

Gradual appearance and disappearance of groups
What is the Natural System?
On the kind of relation between distinct groups
Classification of Races or Varieties
Classification of Races and Species similar
Origin of genera and families

CHAPTER VIII 214-230

UNITY OF TYPE IN THE GREAT CLASSES; AND MORPHOLOGICAL STRUCTURES.

Unity of Type
Morphology
Embryology
Attempt to explain the facts of embryology
On the graduated complexity in each great class
Modification by selection of the forms of immature animals
Importance of embryology in classification
Order in time in which the great classes have first appeared

CHAPTER IX 231-238

ABORTIVE OR RUDIMENTARY ORGANS.

The abortive organs of Naturalists
The abortive organs of Physiologists
Abortion from gradual disuse

CHAPTER X 239-255

RECAPITULATION AND CONCLUSION.

Recapitulation
Why do we wish to reject the Theory of Common Descent?
Conclusion

INDEX 257

Portrait _frontispiece_
Facsimile _to face_ p. 50