LIST OF ILLUSTKATIONS. 



FIG. PAGE 



1. DIAGRAMMATIC Section of an Un incubated Fowl's Egg . . .12 



2. A. Yellow yolk-sphere filled with fine granules. J5. White yolk- 



spheres and ^spherules of various sizes and presenting different ap- 

 pearances '... " ' , * V , . . . . . 15 



3. Section of a Blastoderm of a Fowl's Egg at the commencement of 



Incubation * * . . . . . . 18 



4. Section througli the Germinal Disc of the ripe Ovarian Ovum of a 



Fowl while yet enclosed in its Capsule . . . . . 19 



5. Surface Views of the early Stages of the Segmentation in a Fowl's 



Egg . . , . . .22 



6. Surface View of the Germinal Disc of a Hen's Egg during the later 



Stages of Segmentation . . . ; . . . 23 



7. Section of the Germinal Disc of a Fowl during the later Stages of 



Segmentation . . . . . , '. : . . . 24 



8. A to N. A series of purely diagrammatic representations introduced 



to facilitate the comprehension of the manner in which the body of 

 the embryo is formed, and of the various relations of the yolk-sac, 

 amnion and allantois ........ 29 32 



9. Diagrammatic Longitudinal Section through the Axis of an Embryo. 33 



10. Section of a Blastoderm at right angles to the long axis of the 



Embryo after eight hours' Incubation ...... 46 



