DESCRIPTION Or A NARWAL. I39 



a few remains of animals of the order mollusca in 

 it, and the intestines were filled with a greenish 

 coloured fluid. 



The heart, as in other whales, consisted of two 

 . auricles and two ventricles. It was of a qua- 

 drangular form, and considerably compressed. 



The lungs occupied a considerable proportion 

 of the cavity of the thorax. They rose high in 

 the chest and were not, as in most animals, divided 

 into small lobes. The trachea was short, owing 

 to the shortness of the neck, and divided into four 

 branches or bronchi. The upper part of the 

 trachea terminated in a cartilaginous cavity, ha- 

 ving its diameter somewhat larger than the trachea. 

 From this cavity proceeded a tube, opening longi- 

 tudinally, so as to act like a valve. Each side of 

 the tube consisted of two solid cartilaginous 

 parts, united before, and connected with each 

 other by a strong muscular membrane, the two 

 sides likewise being joined by a similar membrane. 

 The upper end of this tube was surrounded with 

 a cartilaginous ring. When this tube or valve 

 was open, as represented in the plate # , the 

 passage from the nares to the lungs was perfectly 

 free ; but when it was closed, nothing could then 

 enter the lungs. This tube or valve was placed 

 in the posterior part of the blowholes or nasal 

 openings. 



* Plate VI. Fig. 3. 



