FEOG 229 



In some frogs (males) the opening of a vocal 

 sac may be found on each side between the edge 

 of the tongue and the lower jaw. 



II. The alimentary canal. 



Lay the frog on its back and dissect away all 

 of the muscles, bones, etc., covering the ventral 

 side of the body from the pubis to the jaw, being 

 careful not to injure the underlying parts. Leave 

 the glottis and trachea in position. ISTote the 

 manner in which the various organs — heart, liver, 

 lungs, intestine, etc. — are closely packed. Insert 

 a fine-pointed blowpipe — e. g., a glass tube drawn 

 out to a tapering end with rounded edge — into 

 the glottis and inflate the lungs. This will define 

 their position. Do likewise to the bladder by in- 

 serting the end of the blowpipe into the opening 

 of the cloaca. Note the heart, almost surrounded 

 by the lobes of the liver. Eemove the heart, and 

 at present pay attention only to the digestive or- 

 gans. 

 a. The liver. — "What is its position? Shape? 

 Color? Of how many lobes does it consist? What 

 difference in their shape and size? "What is its 

 position relative to the heart ? To the lungs ? Do 

 you find a partition or diaphragm completely 

 separating the cavity in which the heart and 

 lungs lie from that in which the liver and other 

 digestive organs are found ? Turn the liver over 

 towards the left (the frog's right) side, and note 

 the cesophagus leading into the stomach. 



l. The oesophagus. — In what direction does it 

 run ? "What is its shape ? Color ? Diameter ? 

 "What is its relation to the heart ? To the lungs? 



