42 ANATOMY OF A CHELONIAN. 



inflate with a blow-pipe, so as to distend the heart and 

 vessels connected with it. When the organ is blown 

 up the relative size and the form of its parts can be 

 much better seen than \vas possible previously. 



93. Follow now the superior cava on each side, shad- 

 ing insensibly into the venous sinus, and formed a 

 short way from the heart by the union of three large 

 trunks (ii8). Entering the posterior border of the 

 venous sinus, toward the left, is the left hepatic vein ; at 

 the corresponding point on the right side opens a much 

 larger trunk, formed by the junction within the right 

 liver-lobe of the inferior cava and the right, hepatic vein. 



94. Clear away carefully the lymph sinuses and loose 

 areolar tissue surrounding the great vessels springing 

 from the base of the heart, and carefully clean and 

 separate these vessels down to their origin. Extend the 

 neck and remove the skin and connective tissue cover- 

 ing its ventral surface and sides. 



Three vessels spring from the ventricle. That most 

 to the left is the pulmonary artery; that apparently 

 next is the left aorta ; the remaining one is the right 

 aorta, which latter is, however, covered close to the 

 heart by the innominate trunk, which it gives off. On 

 tracing the aortas carefully to the ventricle it will be 

 found that the attachment of the left aorta is rather 

 more to the right than that of its fellow, the two cross- 

 ing close to the heart. 



95. The innominate artery divides almost immediately 

 into the right and left subclavian, and right and left caro- 

 tid arteries. Dissect these out. 



