422 



H. H, Newman and J. T. Patterson. 



Fig. 23. A section taken through the belly-stalk near the posterior tip of the al- 

 lantric entoderm {al. en.). The mesoderm is indistinctly divided into two por- 

 tions. (1) that forming the belly-stalk bands, and (2) that part immediate'y sur- 

 rounding the allantoic tube — this may be called the allantoic mesoderm (al.ms.). 

 The belly stalk is here separated from the wall of the yolk-sac by a space (ex.c ), 

 which is only a part of the general extra-embryonic cavity. X 143. 



