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the intestine, where the pharynx is becoming narrowed to form the 
cesophagus, is rounded, irregular, and extends to right and left and 
eaudally. The right side of the outgrowth is the larger and extends 
further tailward, leaving the cesophagus at a more acute angle than the 
left, a reversal of the adult condition. There is no distinct trachea, as 
the cavity of the esophagus is continued directly into the cavities of the 
right and left lobes of this outgrowth. 
Fic. 11. Model of veins near heart, dorsal view. x 160. 
MODEL OF VEINS NEAR HEART. 
This model represents the venous channels as solid, and includes the 
junction in the sinus venosus of the three large pairs of veins, the jugular 
and the umbilical veins in the body wall, and the vitelline veins in the 
intestinal wall. The sinus venosus is shown as a cavity in the model of 
the heart, so that these two models overlap to a certain extent. Fig. 11 
shows the model as seen from the dorsum of the embryo; Fig. 12 as seen 
from the left side; and Fig. 13 is a view taken from the caudal end of 
the embryo, and a little from the right side. 
The umbilical veins, entering the embryo by the body stalk, run in the 
