LIST OF PLATES 

 Plate Facing Page 



XXII. THE UTERUS OF THE RHESUS MONKEY DURING 



MENSTRUATION 149 



XXIII. STRUCTURE OF THE TESTIS 218 



XXIV. SPERM CELL FORMATION ; THE CRYPTORCHID TESTIS 219 



LIST OF TEXT FIGURES 



Figure Page 



1. Reproduction by lengthwise fission 4 



2. Reproduction by budding 5 



3. Reproduction by spore formation 6 



4. Reproduction by transverse fission 6 



5. Reproduction by eggs and sperm cells, in Hydra 7 



6. Conjugation of a one-celled animal 13 



7. Sperm cells of various animals 15 



8. The human female reproductive tract 86 



9. The corpus luteum 42 



10. Form of the uterus in various animals 49 



11. Diagram of the human female reproductive tract 50 



12. The lining of the uterus (endometrium) 53 



13. Diagram of a uterine gland 55 



14. Implantation of the embryo in rabbit and man 58 



15. Diagram of the reproductive cycle of the sow 67 



16. Diagram of the menstrual cycle and the cycle in 



general 70 



17. Apparatus for studying the activity of uterine muscle 122 



18. Effect of progesterone on the rabbit's uterus 125 



19. Diagram of the reproductive cycle of mammals 140 



20. Form and location of the pituitary gland 142 



21. Diagram of the hormone-alternation theory of the 



cycle 143 



22. Diagram of the menstrual cycle 147 



23. The arteries of the endometrium 150 



24. Diagram, the effect of estrin deprivation 162 



25. The estrin-deprivation hypothesis 163 



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