DISSECTION OF THE PIG EMBRYO 43 



blood toward the head. This vessel is the innominate 

 artery. Branches from the innominate arter}' are given 

 off laterally, going to each fore-limb, the right and left 

 subclavian arteries. Do you find the carotid arteries 

 leading from the innominate arter}^ to either side of the 

 head? Trace the inferior vena cava vein to the heart. 

 With what part of the heart does it connect? The 

 superior vena cava and the inferior vena cava empty into 

 the heart near the same place. The blood from the ante- 

 rior part of the body is collected in the superior vena 

 cava. Trace it and its branches to the neck and fore-legs. 

 Do you find the pulmonary veins? The pulmonary veins 

 carry the blood from the lungs to the heart. What part 

 of the heart? Open the heart. Describe the valves 

 separating the auricles from the ventricles. The two 

 ventricles are separated by a muscular wall, the ventric- 

 ular septum. The two auricles are not separated. The 

 opening between the two auricles is the foramen ovale. 

 Is there any trace of the formation of the auricular 

 septum ? 



Draw a diagram of the circulatory system in the thorax 

 as you have found it in your dissection. Label all the 

 parts. 



Trace the lungs to the mouth. Trace the oesophagus 

 to the mouth. What is the relation of the oesophagus 

 to the trachea and larynx? 



