312 



A YEAR IN SCIENCE 



Mouth 



Pharynx 



Stomach 



The mouth. The 



cavity of the mouth 

 is bounded in front 

 and at the sides 

 by the lips, the 

 cheeks, and the 

 teeth, and below 

 by the tongue. 

 The roof of the 

 mouth is formed 

 by a horizontal 

 plate of bone called 

 the hard palate. 

 Near the middle of 

 the mouth the hard 

 palate ends and 

 is continued back- 

 ward by the soft 

 palate. Hanging 

 down from the 

 roof of the mouth, 

 and separating it 

 from the throat, is 

 the uvula. The entire cavity is lined with a soft' moist 

 covering called the mucous membrane. This membrane 

 is continuous and forms the inner lining of the whole 

 alimentary canal. It secretes a watery fluid known as 

 mucus. 



Teeth. Within the mouth are the teeth which are 



Small 

 Intestine 



Appendix 



Large 

 Intestine 



Figr. 148. The alimentary canal. 



