6o 



THE STUDY OF CHICK EMBRYOS 



Hind-brain 



Nolochord 



Ectoder 



Lens vesicle 



Cavity of fore-brain 



Ant. cardinal vein 



Aortic arch 1 



Optic vesicle 

 ProsencephaJon 



FIG. 58. Transverse section through the fore-brain and eyes of a fifty-hour chick embryo. 



X 50. 



Blastoderm 

 Hind-brai 



Notochord 

 Descending aorta 

 Ant. cardinal vei 

 Ventral aorta- 



'Amnion 

 'horion 



A nt. cardinal vein 



FIG. 59. Transverse section through the optic stalks and hypophysis of a fifty-hour chick 



embryo. X 50. 



