Fig. 10. Section through an ovum, slightly younger than fig. 1. Shewing the primitive cumulus and the columnar character of the cells of one half of the blastoderm.
Fig. 11. Section through an embryo of the same age as fig. 2. Shewing the median thickening of the blastoderm.
Fig. 12. Transverse section through the ventral plate of a somewhat older embryo. Shewing the division of the ventral plate into epiblast and mesoblast.
Fig. 13. Section through the ventral plate of an embryo of the same age as fig. 3, shewing the division of the mesoblast of the ventral plate into two mesoblastic bands.
Fig. 14. Transverse section through an embryo of the same age as fig. 5, passing through an abdominal segment above and a thoracic segment below.
Fig. 15. Longitudinal section slightly to one side of the middle line through an embryo of the same age.
Fig. 16. Transverse section through the ventral plate in the thoracic region of an embryo of the same age as fig. 7.
Fig. 17. Transverse section through the procephalic lobes of an embryo of the same age. gr. Section of hemicircular groove in procephalic lobe.
Fig. 18. Transverse section through the thoracic region of an embryo of the same age as fig. 8.
Fig. 19. Section through the procephalic lobes of an embryo of the same age.