FIGURE 



49. Gastrula of Chick 



50, 51. Four secondary germ 



layers . 



52-56. Diagrammatic longitu- 

 dinal and transverse sec- 

 tions through the ideal 

 Primitive Vertebrate 



57, 58. 



59. 



60. 

 61. 



62-C9. Diagrammatic trans- 

 verse sections through 

 the mostimportant germ- 

 forms of the ideal Primi- 

 tive Vertebrate 



70. Diagrammatic transverse 



sections through various 

 mammalian germs (ex- 

 plaining the separation 

 of the intestine from the 

 yelk-sac). 



71. Gastrula of Mammal . 



72. Intestinal germ-vesicle of 



Mammal 



73. Transverse section through 



the intestinal germ- 

 vesicle of Mammal 



74. Exoderm-cells of the above 

 7 5. Entcderm-cells of the above 

 76. Transverse section through 



77-81. Intestinal germ-vesicle 



of Babbit 



82, 83. Germ-area of Rabbit 

 84. 

 So. 



