94 



from the normal, and it occurs when the subaortic musculature comes 

 up high, invading the pars membranacea septi. It is the left side 

 of the heart from which Fig. 2 was drawn. The subaortic musculature, 

 shows some of the various directions which its 



as drawn in Fig. 1 



Coronary Artery 



Thread 



Right Corouary 

 Cusp 



Main Bundle 



Coronary Sinus 



Reticulum 



Nodule of Muscle 



pushing main Bundle 



to other side 



Septal Cusp turned 



back 



Right Ventricle 



Aorta 



Non-coronary Cusp 



Cut edge of Mitral 

 ^ Cusp 



\ 1/ / \\ — Dissection of Bursa 

 'i^ 'MrM:^^'^ ^ Suh Aortic Musclea- 

 ture of Septum 



Left Ventricle 



Right Auricle 



Pars Mem. 

 Septa 



Right Septal 

 Branch 



Fig. 2. 



fibres may take. In this dissection the left septal branch first appears 

 below the transverse fibres, about the end of the index line marked 

 "Left Ventricle", but they have lost their color and do not show in 

 the drawing. The bursal space is held out by a thread inserted for 

 the purpose, and the main bundle is seen lying at the bottom of it. 



