LIST OF FIGURES 



PAGE 



Macrogamete and Microgamete 717 



Ovum and Spermatozoon 718 



Structure of a Spermatozoon 721 



Spermatozoon of a Newt. After Ballowitz 722 



Oogenesis and Spermatogenesis. After Boveri 723 



Ovum and Spermatozoon 724 



Sperm-development and Ovum-development 725 



Reducing or meiotic division 726 



Crossing over of Chromosomes 727 



Different Modes of Ovum Segmentation 733 



Different Types of Ova and their Cleavage 734 



Typical Gastrulation 736 

 Early Stages in Development of Amphioxus. After Hatschek 737 



Continuity of the Germ-cells 739 



Typical Life-curves of Plants and Animals 759 



Zoaea Larva of a Crab. After Roule 761 



Megalopa Larva of a Crab. After Roule 762 



Early Stages of Angler-fish. After Bowman 763 



Alternation of Generations in Hydroid. After Allman 768 



Strobila stage in life-history of Jellyfish 769 



Diagram of Alternation of Generations 770 



Life-history of Liver-Fluke 771 



Alternation of Generations in Fern 772 



Diagram of Alternation of Generations 773 



Prothallus of Fern. After Strasburger 781 



Fertilisation and Early Development in Flowering Plants 783 



Free-swimming larva of a Sea-Worm 788 



Life-history of the Common Eel. After Schmidt 789 



Larva of Rock-lobster. After Roule 790 



Trochosphere larva of a Sea-Worm 792 



Successive Geological Ages 817 



Evolution of Species of Paludina. After Neumayr 819 



Evolution of Nautiloid Shells. After Lull 820 



A Trilobite 822 



Evolution of Elephants. After Lull 823 



A simple multicellular Animal, Orthonectid 827 



Australian Collared Lizard. After Saville Kent 833 



Antlers of Stag, from second to sixth year 842 



Mastigamoeba, at once amoeboid and flagellate 845 



Colony of flagellate Infusorians. After Saville Kent 862 



