HOW ANIMALS DEVELOP 



FIG. PAGE 



i6. spemann's exchange experlment 



IN the newt 65 



17. an organizer graft in the newt 68 



18. AN organizer graft IN THE CHICK 



facing page 70 



19. A GRAFTING EXPERIMENT IN THE 



SEA-URCHIN 74 



20. DEVELOPMENT OF THE DRAGON-FLY 76 



21. DEVELOPMENT OF THE EYE IN 



VERTEBRATES 79 



22. SELF-DIFFERENTIATION OF THE LEG 



BONES OF A CHICK facing page ^2 



23. DEVELOPMENT OF THE EYE IN THE 



OCTOPUS 89 



24. CATERPILLAR 91 



25. WHITEMOOR MARSHALLING YARD, 



L.N.E.R. facing page 93 



26. DIFFERENT TYPES OF PLACENTA IO7 



27. GROWTH OF MAN AND GORILLA IIO 



28. VEGETARIAN AND CARNIVOROUS TAD- 



POLES 112 



29. EFFECTS OF THE PITUITARY GLAND 



facing page 114 



30. FACES OF MEN AND DOGS facing page 1 1 ^ 



