Zoological Philosophy

Degradation and Simplification in the Organic Structure

Mammals

Birds

Invertebrate Animals

Reptiles

Fish

Cirrhipedes And Annelids

Crustaceans

Arachnids 9th Rank

Insects

Worms (11th Rank)

Radiates (12th Rank)

Polyps

Modifications in Plants

Infusorians

The Laws of Evolution of Lamarck