Fig. 4 Wax plate reconstruction of caudal end of the medullary tube and 

 hind-gut with the belly stalk vessels viewed from the side. X 100. 



Fig. 5 Wax plate reconstruction of a section of the heart with the endothelial 

 tube in position viewed from the cephalic aspect. X 100. 



Fig. 6 Wax plate reconstruction of the heart viewed from the cephalic aspect. 



X 100. 



Fig. 7 

 X 100. 



Wax plate reconstruction of the heart viewed from the caudal aspect. 



326 



