Sup. vena cava 



Aorta 



Pulmonary trunk 



DEVELOPMENT OF THE HEART 



Septum II Foramen ovale 



255 



L. atrium 



Septum I 



Inferior vena cava 



Coronary sinus 

 Bicuspid valve 



L. ventricle 



FIG. 264. Lateral dissection of the heart of a 65 mm. human fetus, viewed from the left side, 

 showing the septa and the foramen ovale. X 8. 



Sept. I 



L. vent 



FIG. 265. Lateral dissections of the human heart, viewed from the left side: A, from a 

 22 mm. embryo; B, from a 105 mm. fetus. Bic. va., Bicuspid valve; Cor. sin., coronary sinus; 

 For. oi>., foramen ovale; I.v.c., inferior vena cava; L. atr. vent, c., left a trio- ventricular canal; 

 L. *.,. left ventricle; Put. a., pulmonary artery; Sept. I, Sept. II, septum primum and septum 

 secundum. 



