6o 



THE STUDY OF CHICK EMBRYOS 



Hind-brain 



Notochord 



Ectoderm 



Lens vesicle 



Cavity of fore-brain 



Choriort 

 Amnion 



Ant. cardinal win 



Aortic arch 1 



<ptic vesicle 

 Prosencephalon 



FIG. 5 8.-Transverse section through the fore-brain and eyes of a fifty-hour chick embryo. 



X 5. 



Blastoderm 



Hind-brain 



Notochord. 

 Descending aorl 

 Ant. cardinal vei; 

 Ventral aortOf 



Optic vesi 

 Mesenchyme. 



Amnion 

 'horion 



Ant. cardinal vein 



Ectoderm 

 Pharynx 

 Rathke's pouch 



Fore-brain 



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



embryo. X 50. 



