Discusses extinction of ammonites.

Discusses August Krohn’s cirripede research and Krohn’s correction of his own work.

Discusses origin of dog in connection with origin of man.

Comments on the guinea-pig in South America.

Notes K. E. von Baer’s view of species.

Mentions difficulty of crossing rabbit and hare.

Agrees with Hooker’s views on variation under cultivation and in nature.

Regrets use of term "natural selection", would now use "Natural Preservation".