1 88 VERTEBRATES 



Remove the eighth vertebra and study it separately. Note 

 the centrum, the neural arch, and the transverse processes, 

 which are really small ribs. The opening at the base trans- 

 mits the cervical artery. The other irregularities are called 

 sygapophyses. Of what use are they? 



Draw end view (X2). 



(5) The first vertebra next to the head is called the 

 atlas, and the second axis. Study their relation to one an- 

 other and how they fit together. Can you see why the 

 respective names were given? Have all the vertebrae true 

 ribs? Observe how the ribs project from the spinal column, 

 and also how they are supported. 



(6) Study the skull. The opening into it from the spinal 

 column is the foramen magnum. The bones surrounding 

 this are the occipitals. The bar connecting the front with the 

 back part is the quadratojugal bar. At the back end of 

 this is the quadrate bone attaching the lower jaw to head. 

 The upper part of the skull is composed of the parietal, 

 the frontal and the nasal bones, ending in the premaxillary, 

 or upper mandible. 



Draw the under and upper surfaces of the skull. 



IV. The Nervous System. — (i) Cut off a portion of 

 the roof of the skull, being careful not to injure the eyes 

 or the internal parts. This exposes a portion of the brain 

 which is similar in appearance to the brains of the other 

 animals studied, but is more compact and fits its cavity 

 closer. Remove the surrounding bones and lay the brain 

 bare. 



(2) Examine the surface of the brain. Can you name 

 the parts? How do the parts compare with the same parts 

 of the brain of the frog? Of the fish? What part is most 



