Fifi;. 3 Heart sliown in fi^. 2 broken open from Ix'liind aerording to MacCalhun's 

 mctliod. SS, superficial au(Uleej).sino-spiral sheet (Uit transversely; LRV, the mus- 

 cle band from the membranous septum to the right ventricle cut transversely. 

 The tendon of the conus, comis ])art of the aortic septum, is shown on I he medial 

 side of the (ronus, X'. On the ])()sterior side of the aortal he a1 rio-vent ricular bun- 

 dle is seen. TR, posterior triangular field extending downward into the raphe. 



