ILLUSTRATIONS 



FIQ. PAGE 



1. Asexual Reproduction, an Amoeba in Division 21 



2. Asexual Reproduction by Means of Runners 22 



3. Hermaphroditism in the Tapeworm Proglottid 24 



4. Rhopalura, an Example of Extreme Sexual Dimorphism 26 



5. Sexual Reproduction in Fupus .' 26 



6. Ulothrix, a Primitive Type of Sexual Reproduction 28 



7. An Adaptation for Self-pollination 30 



8. An Adaptation for Cross-polh'nation 34 



9. Diagram of Gametogenesis 38 



10. Diagram to Illustrate Fertilization 39 



11. Formation of Pollen Grains in the Lily 40 



12. Fertilization in the Embryo Sac of the Lily 41 



13. Entrance of Spermatozoon through Membrane of Egg of Star-fish ... 42 



14. Diagram Showing the Distribution of Sex Chromosome in Protenor . . 43 



15. Identical Quadruplets in Nine-banded Armadillo 44 



16. Diagram to Illustrate Inheritance of Sex-linked Character 48 



17. Diagram Showing Union of like Gametes 52 



18. Diagram to Illustrate Mendelism in a Cross between Long-Spiked and 



Short-Spiked Wheat 54 



19. Diagram to Illustrate Gamete Formation in a Dihybrid in Indepen- 



dent Inheritance 59 



20. Diagram to Illustrate Gamete Formation in a Dihybrid in Linked 



Inheritance 63 



21. Diagram to Illustrate Crossing-over 64 



22. Curves Showing the Limiting Values of the Coefficients of Inbreeding 



with Various Systems of Matings 84 



23. Graphs Showing the Total Inbreeding and Relationship Curves for 



the Jersey Bull, King Melia Rioter 14th 86 



24. Graphs Showing the Reduction of Heterozygous Individuals and of 



Heterozygous Allelomorphic Pairs in Successive Generations of 



Self-fertilization 90 



25. Graphs Showing the Increase in the Body Weight with Age for the 



Males of Inbred Albino Rats 107 



26. Graphs Showing the Increase in Weight of Body with Age for Differ- 



ent Series of Male Albino Rats 108 



11 



