FEOG 227 



ors? "Which muscles flex the foot? Extend the 

 foot ? What reasons can you give for the large 

 size of the thigh muscles ? Of the gastrocnemius ? 

 For the great difference in size between the mus- 

 cles of the anterior and those of the posterior 

 limb? When the frog's leg is flexed upon the 

 thigh, does it lie in the same position as the 

 human leg ? 



Compare the arrangement of the principal mus- 

 cles of the frog with the corresponding muscles 

 of the human body, as shown on charts, ana- 

 tomical plates or on a manikin. 

 C. — The Digestive System. 

 I. The mouth-cavity. 



Pull down the lower jaw and open the mouth 

 to its widest extent. 



What is the shape of the mouth-cavity ? Can 

 it be enlarged ? If so, in what directions ? What 

 external organs mark the posterior boundary of 

 the mouth-cavity ? Are there any lips ? What is 

 the color and texture of the mucous membrane 

 lining the cavity ? Can the position of the eyes 

 be determined by an examination of the roof of 

 the mouth ? Press upon the external surface of 

 the eyeball. What change takes place in the 

 mucous membrane of the roof of the mouth ? 



Examine the roof of the mouth and find the 

 following structures : 



a. The maxillary and vomerine teeth. — These 

 were examined in the skeleton. Note again their 

 position, arrangement, prominence, etc. 



h. The posterior nares. — How many are there? 

 What is their position with regard to the anterior 



