CHICK EMBRYO OF TWENTY-SEVEN SEGMENTS 



folds now forms the outer layer of the chorion and the inner layer of the amnion. The meso- 

 dermal folds of the amnion have not united. 



Spinal cord - 

 Mes. segment 



Chorion 

 flmnion 

 Ectoderm 



Enfoderm 

 Myocardium 



End 

 or, 



,'othelium 

 or hear!" 



FIG. 59. Transverse section through, the sinus venosus and common cardinal veins of a fifty-hour 



chick embryo. X 50. 



Chorion 

 Amnion 



Nofothord 

 Dorsa/aortx 



L.vitejline. 

 vein 



Splanchnic 

 mesoderm' 



Post caret. 

 Vein 



Splanchnic, 

 mesoderm 



FIG. 60. Transverse section through the anlage of the liver of a thirty-six-hour chick embryo. X 50. 



Section through the Anlage of the Liver (Fig. 60). In this section the cavity of 

 the fore-gut is narrow, the gut being flattened from side to side. Ventrad there are evaginated 

 from the entoderm two elongate diverticula which form the anlages of the liver. On either side 



