80 STUDIES OF ANIMAL TYPES 



Note the tongue. Is it attached like the tongue of a 

 frog ? Observe the forked extremity of the tongue. 



D. INTERNAL FEATURES. Lay the lizard on its back 

 on a pine board and stretch the legs to the right and 

 left and tack them to the board. Also put a tack through 

 the tail and through the upper jaw, leaving the lower 

 jaw free. 



Seize the lower jaw and pull it upward to show the size 

 of the mouth opening. Find the teeth on the jaws and 

 determine the shape and size. Note the size, shape, and 

 attachment of the tongue again. 



At the root of the tongue find a small opening, the glot- 

 tis. This is the entrance to the windpipe that leads to the 

 lungs. 



Begin immediately back of the fore legs and cut through 

 the floor of the abdomen in a median line to the anal aper- 

 ture. Be careful not to injure any of the internal organs. 

 Now make a transverse cut just behind the front legs and 

 turn the walls of the abdomen to the right and left and pin 

 or tack down to the board. 



Respiratory apparatus. Use the inflating apparatus 

 described in the Appendix and insert the point into the 

 glottis, and inflate the lungs. Trace the windpipe to the 

 lungs. Note that it bifurcates, a branch going to each of 

 the lobes of the lungs. What is the shape and color of 

 the lobes ? How far back does each lobe extend ? 



Circulatory organs. Note the heart on top of the wind- 

 pipe and lungs. Of course, in the natural position of the 

 animal, the heart would be ventrad of these organs. The 

 heart is inclosed in a thin sac, the pericardium. Pinch up 

 a fold of this sac, cut through it, and remove the heart, 

 being careful not to sever any of the blood vessels, Note 



