ORGANS OF DIGESTION. 113 



There are seven openings into the pharynx: the two 

 posterior nares (Fig. 18), opening anteriorly from the- 

 reof; a Eustachian tube on each side; the esophagus; and 

 the larynx, leading into the trachea. The mucous mem- 

 brane lining the pharynx contains many simple microscopic 

 mucous glands. 



VISCERA. 



The body cavity known as the ccelom must be opened 

 before the rest of the alimentary canal can be displayed. 

 The entire ventral wall of the thoracic and abdominal cavi- 



FIG. 59. VISCERA OF THE HUMAN BODY. (Deaver.} 

 co, Colon; li, liver; lu, lung; si, small intestine; st, stomach. 



