124 INTRODUCTION TO ZOOLOGY. 



The Heart. 



1. Remove the skin from the head. Below and 

 back of the ear, find an irregular pink mass, the 

 parotid salivary gland. 



2. In the angle between the branches of the lower 

 jaw, find two roundish bodies, the submaxillary sali- 

 vary glands. 



3. See the muscle which covers the back part of 

 each side of the lower jaw. This shuts the mouth. 

 Where is it attached? Cut it away. 



4. Thoroughly clean the lower jaw and examine 

 the teeth. The front ones are incisors. Those farther 

 back are molars. How many of each kind in the 

 upper jaw? How maity of each kind in the lower jaw? 



5. How is the lower jaw attached to the skull? 

 DraAV the lower jaw. 



6. Find the occipital foramen, through which the 

 spinal cord passes into the skull. 



7. In front of the foramen, find the two occipital 

 condyles. Thoroughly clean the first two vertebrae of 

 the spinal column. The first one is the atlas, the 

 second one is the axis. How do they differ? 



Interior of the Head. 



1. Cut awajr carefully the top and back of the 

 skull, exposing the brain. Find two coverings, one 

 closely attached to the skull, the other covering the 

 surface of the brain. The first one is called the dura 

 mater, and the second one is called the pia mater. 



2. Identify the cerebrum. Notice the groove be- 

 tween the two lobes. 



3. See the band of white fibers connecting the two 

 lobes. 



4. Identify the cerebellum, behind and under the 

 cerebrum. 



