Criticises at length the concept of submerged continents attaching islands to the mainland in the recent period. Notes drastic alteration of geography required, the dissimilar species on opposite shores of continents, and differences between volcanic islands and mountains of mainland areas. Admits sea-bed subsidence, but not enough to engulf continents. Denies that theory can explain island flora and fauna.

Considers Edward Forbes’s idea a check on study of dissemination of species.

CL’s comments on Origin. Mentions corrections to last chapter suggested by CL.

Comments on lack of peculiar bird species on Madeira and Bermuda. Emphasises importance of American types in Galapagos.

Denies necessity of continued creation of primitive "Monads".

Denies need for new powers and any principle of improvement.

Discusses gradations of intellectual powers.

Adaptive inferiority and extinction of groups of species and genera.

Asserts that climate is less important than the struggle with other organisms.

Suggests an experiment involving primroses and cowslips.

The chapter on hybridisation.

Rudimentary organs.

Gives opinion of Lamarck’s work.