100 PRACTICAL ZOOLOGY. 



2. Seize the tongue, and draw it forward from its sheath 

 in the floor of the mouth. Observe its black, forked 

 tip ; tack it down. 



3. Above the tongue find a small opening, the entrance 

 to the windpipe. It is called the glottis. 



4. Insert a blowpipe (glass tube) into the throat through 

 the mouth; pinch the walls of the gullet closely 

 around the blowpipe, and inflate the wide gullet and 

 stomach. What does the snake eat, and how does 

 he eat? 



5. For inflating the lung, a tube with a small point is 

 better ; draw out a small glass tube, and connect with 

 a rubber tube ; insert the point in the glottis, and in- 

 flate. This locates the pink lung, with its posterior, 

 thin walled extension, or air-sac. 



6. Trace, from the glottis to the lung, the ringed wind- 

 pipe, or trachea. Only one lung is developed; look 

 for the rudiment of the other. 



7. The heart will be noticed on account of its beating; 

 the part of it farthest from the head is the ventricle; 

 nearer the head find two parts, the right and left 

 auricles. These two contract at the same time, just 

 before the contraction of the ventricle. The heart is 

 in a thin sac, the pericardium ; pinch up a fold of 

 this with the forceps, and cut through it, and remove 

 that part of it covering the heart, very carefully 

 avoiding blood-vessels. 



8. Find a blood-vessel arising from the ventricle just 

 between the auricles, and passing forward between 

 them, curving around over the gullet to the posterior 

 part of the body. This is the main artery, or aorta; 

 look for its branches running to the head. 



