FISH. 115 



1. The pericardial cavity and the septum sep- 



arating it from the abdominal cavity. 



2. The heart . 



(a) The sinus. 



(b) The auricle. 



(c) The ventricle. 



(d) The bulbus (conus). 

 Diagram 



3. Find the veins coming to the heart : 



(a) The hepatic veins, passing through the 

 septum from the abdominal cavity and 

 opening into the sinus. 



(6) The pre-caval veins (ducts of Cuvier), one 

 on each side formed by the union of 

 the jugular vein from the anterior and 

 of the cardinal vein from the posterior 

 region, passing ventrally along the sep- 

 tum and opening into the sinus. 



4. Trace the ventral aorta from the bulbus and 



find its branches. 



5. Find the dorsal aorta (dorsal to the air-blad- 



der) and trace it forward into the ceph- 

 alic circle. 



Diagram of the veins and arteries. 

 IV. Exoskeleton. 



Take off several scales from different parts 

 of the body. Examine with a low 

 power. 

 Sketch. 



