The Outline of Science: A Plain Story Simply Told. E-book. Formato PDF John Arthur Thomson   -  Forgotten Books, 2017  - 

The Essential Characters of Vertebrates — The Pioneers — The sea-squirts — The Lancelets — The round-mouths — Fishes — Amphibians — Reptiles — Tortoises and Turtles.

Herbert Spencer. E-book. Formato PDF John Arthur Thomson   -  Forgotten Books, 2017  - 

Another aspect of interest is that Spencer was an arch-heretic, one of the flowers of Nonconformity.