2F.2B. Fishes.
Selachii.
Ganoids.
Teleosts.
Dipneusts.
2F.2C. Amphibia.
2F.2D. Reptiles.
2F.2E. Birds.
2F.2F. Mammal.
Monotremes.
Marsupials.
Placentals:—
Rodents.
Edentates.
Ungulates.
Cetacea.
Sirenia.
Insectivora.
Cheiroptera.
Carnassia.
Primates.
(This classification is given for the purpose of explaining Haeckel's use of terms in this volume. The general reader should bear in mind that it differs very considerably from more recent schemes of classification. He should compare the scheme framed by Professor E. Ray Lankester.)