110 Dr. J. A. Mc William. The Structure and Rhythm [Jan. 29, 



This tubular vessel becomes continuous with the ventricle at its mitral 

 orifice, which is placed a little below the middle of the dorsal aspect 

 of the ventricle. 



Eel's Heaet (diagrammatic). 



J.V. Jugular Veins (right and left) . 



Au. Auricle. 



V. Ventricle. 



B.A. Bulbus Arteriosus. 



L. Liver. 



1. Ostial parts of Sinus. 



2. Interjugular part of Sinus. 



3. Main part of Sinus. 



4. Basal wall of Auricular Chamber continuous with ventral wall of Sinus. 



5. Tubular communication between Auricle and Ventricle (canalis auricularis) . 



6. 6. Arteries passing to Ventricle. 



7. Veins on surface of Ventricle. 



When the circulation is going on this disposition of the parts of the 

 heart is rendered extremely obvious by the differences in colour pre- 

 sented by the various portions. The sinus is of a blue colour ; the 

 auricle is dark red ; the ventricle is of a lighter red tint. When the 

 ventricle is turned upwards, the blue ventral prolongation of the sinus 



