44 THE THORACIC VISCERA, BUCCAL CAVITY, 



what is known as the bronchial tree. The terminal 

 twigs of this system end in the air-sacs or alveoH, little 

 membranous bags, in the walls of which the capillaries 

 of the pulmonary artery are distributed. 



D. DISSECTION OF THE BUCCAL CAVITY. 



Remove the skin from the head. Lay open the 

 mouth on one side by cutting tJiroiLgJi the cheek with a 

 pair of scissors, and contimnng the cttt backward 

 across the bone with bone forceps or saw. 



1. The Roof of the Mouth. 



a. The Hard Palate, formed by the palatine 

 processes of the maxillary and palatine bones. It is 

 covered by pigmented mucous membrane which is 

 raised into a number of transverse ridges. The soft 

 palate is continued backward from this and ends in a 

 free notched border. 



b. The Tonsils are two pinkish-gray eminences 

 lying lateral to the soft palate and above the root of 

 the tongue. 



c. The Teeth. Verify the dental formula i. |, 

 c. |, pm. f , m. |. 



2. The Floor of the Mouth. 



a. The Tongue is attached along the greater 

 part of its length to the floor of the mouth. The 

 mucous membrane covering the upper surface shows 

 three different kinds of papillae : the circu^nvallate, 

 four in number, arranged along two converging lines 

 at the root, of the tongue ; the ftmgiform, found 

 generally over the dorsal surface and especially thick 

 at the tip ; the filiform, which toward the root are 

 larger than in front, and end in free notched borders. 

 They are thickly scattered over the whole dorsal surface. 



