pt. I. The descent or origin of Man (1. The evidence of the descent of Man from some lower form
2. On the manner of development of Man from some lower form
3. Comparison of the mental powers of Man and the lower animals
4. Comparison of the mental powers of Man and the lower animals, continued
5. On the development of the intellectual and moral faculties during primeval and civilised times
6. On the affinities and genealogy of Man
pt. II. Sexual selection 98. Principles of sexual selection
9. Secondary sexual characters in the lower classes of the animal kingdom
10. Secondary sexual characters of insects
11. Insects, continued : order Lepidoptera (butterflies and moths)
12. Secondary sexual characters of fishes, amphibians, and reptiles
13. Secondary sexual characters of birds
17. Secondary sexual characters of mammals
18. Secondary sexual characters of mammals, continued)
pt. III. Sexual selection in relation to Man, and conclusion (19. Secondary sexual characters of Man
20. Secondary sexual characters of Man, continued
21. General summary and conclusion).