160 REPTILIA (the turtle) 



at the base of the tongue. Put about a tablespoon- 

 ful of chloroform into the blowpipe and blow it into 

 the lungs. Now tie a string tightly around the neck 

 to keep the air out of the trachea, and let the turtle 

 lie fifteen or twenty minutes. Another method of 

 killing preferred by some is simply to place the tur- 

 tle on its back in the ^'killing box." Wrap a cloth 

 well saturated with chloroform about its head. Close 

 the lid tightly and allow the turtle to remain about 

 twenty minutes, then tie a string very tightly around 

 its neck. 



(2) Slit open the skin of the ventral side of the neck and 



expose the trachea, esophagus, and the strong mus- 

 cles of the neck. 



(3) Remove the plastron by cutting through the skin along 



its margin and sawing or cutting through the plas- 

 tron where it joins the carapace. With a sharp scal- 

 pel dissect away the muscles from the inner surface 

 of the plastron, cutting very close to it, so as to leave 

 the internal organs uninjured and in place. 



(4) Cut away the pericardium, the semitransparent 



membrane covering the heart, taking care not to cut 

 the blood-vessels. Observe the beating of the heart. 

 What is the order of contraction — auricles and ven- 

 tricle — or the reverse? 



(5) With a sharp scalpel cut the peritoneum along the 



middle line, beginning just posterior to the heart and 

 continuing posteriorly. In doing this, place the 

 point of the scalpel edge up under the membrane and 

 cut outward, taking great care not to injure amj under- 

 lying organs. 



(6) Cut the string about the neck. Insert a blowpipe in 



the glottis and inflate the lungs, and quickly tie a 

 string tightly around the trachea to keep them in- 

 flated. Now you are ready to begin the study of 

 the internal organs. 



(7) First note their position in the body-cavity. 



(a) Where is the heart situated with reference to the di- 

 gestive organs? 



