168 



TEXT-BOOK OF EMBRYOLOGY. 



Neural crest 



Myotome \ 



f Cutis plate 



i Muscle plate 

 Scl. 1 



Pronephros 



Parietal mesoderm~- 

 Intesti 



Myotome 



Sclerotome 



Visceral mesoderm 



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

 point where sclerotome is closely attached. KoUmann. 



Neural tube HP*! 



Intersegmental . 

 artery 



Intersegmental - 

 artery 



Ectoderm 



v i *t!t -> 

 tt)*.M/4X 



3M& 



SSZL 



/i"" Sclerotome 





~S5Tit * 



^?%v 



^g^i 



**ii5^-- 

 ^*s& B*J.- 



>' Myocoel 



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

 the 3rd week. Kollmann. 



