George John Romanes and the Struggle for Darwin's Mantle

Scientific Evidences of Organic Evolution

Animal Intelligence

Mental Evolution in Animals. with a Posthumous Essay on Instinct by Charles Darwin

Darwin and after Darwin

Darwinism Illustrated

Mental Evolution in Animals

Darwin, And After Darwin Vol 3 Post-Darwinian Questions

Darwinism of Darwin, and of the Post-Darwinian Schools

Our Common Cuckoo and Other Cuckoos and Parasitical Birds : An Attempt to Reach a True Theory of Them by Comparative Study of Habit and Function

Mental Evolution in Man, Origin of Human Faculty