THE DEVELOPMENT OF THE HEART IN SHAD. 

 H. D. SEXrOR. 



Lateral plate fN°">-| Lateral plan 

 IchordI 



Mandibu 

 lodermal pouch 



P M. descending 

 Entodermal pharynx! 

 closed 



6D 



P M 

 Endocardium 



Endocardium 



Otocyst 



Fig. 6. — Diagram of the ventral surface of a reconstruction of the peri- 

 cardial region of shad, stage of 26 somites X T*() diams. See explanation of 

 figures, footnote on page 22(i. 



Ttte American .Toi-rnai, of Anatomy. — Vol. IX. No. 2. 



