Text Book of Biology, Part 1: Vertebrata

First course in biology

Bailey, L. H. (Liberty Hyde); Coleman, Walter Moore

On the Origin of Species By Means of Natural Selection Or, the Preservation of Favoured Races in the Struggle for Life

Charles Darwin

Darwin, and After Darwin, Volumes 1 and 3 An Exposition of the Darwinian Theory and a Discussion of Post-Darwinian Questions

George John Romanes

On the Origin of Species by Means of Natural Selection or the Preservation of Favoured Races in the Struggle for Life. (2nd edition)

Charles Darwin

The Variation of Animals and Plants under Domestication

Charles Darwin

Evolution, Old & New Or, the Theories of Buffon, Dr. Erasmus Darwin and Lamarck, as compared with that of Charles Darwin

Samuel Butler