The semilunar valves ( the pulmonary and aortic valves ) are formed from four thickenings at the cardiac end of the truncus arteriosus.
3.
Nearer its pyloric than its cardiac end is a well-marked notch, the " incisura angularis ", which varies somewhat in position with the state of distension of the viscus; it serves to separate the stomach into a right and a left portion.