THE HEART 



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are muscular sleeve-like structures which develop from the endocardium of the original 

 atrio-ventricular opening, while on the other side of the interventricular septum three 

 valves are formed in continuity with the wall of the ventricle itself. They have thus the 

 appearance of cordae tendinae, with tasselated ends free and bent inwards towards the 

 cavity of the left ventricle. 



Fig.g. The heart and associated organs, side view. «, stage 13; 6, stage 18; r, stage 3.. «», atr.um; 

 CO, conus arteriosus ; k, opisthonephros ; /, Hver ; /«, lung ; oe, oesophagus ; sv, sinus venosus ; vc, left anterior 

 vena cava. 



