164 



TEXT-BOOK OF EMBRYOLOGY. 



Myotome 



Pronephros - 



Parietal mesoderm 

 Intestine 



Umbilical 



Vein 



Visceral mesoderm 



FIG. 142. ^Transverse section of human embryo of the 3rd week. Sc/. 1 , Break in myotome at 

 point where sclerotome is closely attached. Kollmann. 



Neural tube 



Intersegmental 

 artery 



Intersegmental 

 artery 



Ectoderm 



Sfc/i/^ Sclerotome 



Myocoel 



FIG. 143. Three primitive segments from sagittal section of human embryo of 

 the 3rd week. Kollmann. 



