2s6 



THE DEVELOPMENT OF THE VASCULAR SYSTEM 

 Septum II Foramen ovale 



Sup. vena cava 



Scpliim I 



Inferior vena cava 



GjJ y — Coronary sinus 

 Bicuspid valve 



L. ventricle 



Fig. 264.— Lateral dissection of the heart of a 65 mm. human fetus viewed f om (he left ide, showing 

 the septa and the foramen ovale. X 8. 



Sup. V. c. 



Sept I 

 I V c 



Co) sin. ^■ 

 r I vent 



L atr. 



vent. c. 



L. vent 



A B 



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. ov., foramen 

 ovale; I.v.c, inferior vena cava; L. atr. vent, c ., left atrio-ventricular canal; L. vent., left ventricle; Piil. 

 a., pulmonary artery; Sept. I, Sept. II, septum primum and septum secundum. 



