DEVELOPMENT OF THE HEART 



253 



Aorta 



Sept. I 



Aorta, 



Sept. II 



L. vent. 



FIG. 261. Lateral dissections of the human heart, viewed from the left side: A, 6 mm.; 

 B, 9 mm.; C, 12 mm. (B is based on a reconstruction by Tandler). X about 38. Cor. sin., 

 Coronary sinus; D. end. c., dorsal endocardial cushion; For. ov., foramen ovale; Int. /or.,inter- 

 atrial foramen; I. v. c., inferior vena cava; L. atr., left atrium; L. va. s. v., left valve of sinus 

 venosus; L. vent., left ventricle; Put. a., pulmonary artery; Put. v., pulmonary vein; Sept. I, 

 Sept. II, septuni primum, septum secundum; Sup. v. c., superior vena cava; V. end. c., ventral 

 endocardial cushion. 



Foramen mate 



R. valve of sinus venosus 



Inf. vena cava- 



Sup. vena cava 

 Septum II 



orta 



Semilunar valve of 

 pulmonary artery 



R. ventricle 



FIG. 262. Lateral dissection of the heart of a 65 mm. human fetus, viewed from the right side. 



X 12. 



