viii CONTENTS. 



PAGE 



CHAPTER IV. 



Reproduction and Life-History of Animals. 



Modes of Reproduction — The Reproductive Cells — Fertilisation 

 — Segmentation — The Germinal Layers — Origin of Organs — 

 The Ovum or Cell Theory — The GastrKa Theory — The 

 Fact of Recapitulation — Continuity between Generations — 

 Heredity, .... . . 46 



CHAPTER V. 



Past History of Animals (Paleontology). 



The Geological Record — Palssontological Series — Extinction of 

 Animals — Tabular Survey of the Appearance of Animals 

 in Time, ....... 67 



CHAPTER VI. 



Geographical Distribution of Animals. 



Pelagic — Littoral — Deep-sea — Fresh-water — Terrestrial ^- Geo- 

 graphical Areas, ...... 74 



CHAPTER VII. 



The Evolution of Animals (iETioLOGY). 



Doctrine of Descent — Theory of Evolution — Primary Factors — 



Secondary Factors, ...... 79 



INVERTEBRATE ANIMALS. 



CHAPTER VIII. 



Protozoa. 



Protozoa and Metazoa — Plants and Animals — General Classifica- 

 tion of Protozoa — Special Types : Amosba, Paramoecium, 

 Vorticella, Gregarina, Monocystis — Systematic Survey of 

 Protozoa, ■•■•... 91 



