510 



ANGIOLOGY 





like aperture lies obliquely, and is guarded by two halves, the right and left venous 

 valves; above the opening these unite with each other and are continuous with a 



Left duct of 

 Cuvier 



Opening into Eight duct of 

 atrium Cuvier 



FIG. 464. Dorsal surface of heart of human embryo of thirty-five days. (From model by Hi.) 



Keptum spurium 



Opening of sinus venosus 

 Left venous valve 



Septum primum 



Right venous 

 valve 



Spina vestibuli 



Posterior endocardia! 

 cushion 



Atrial canal 



Septum inferius 

 FIG. 465. Interior of dorsal half of heart from a human embryo of about thirty days. (From model by His.) 



fold named the septum spurium; below the opening they fuse to form a triangular 

 thickening the spina vestibuli. The right venous valve is retained; a small 



