132 LABORATORY MANUAL 



From these centers branches lead to all parts of the 

 head and to some of the internal organs. 



Examine the spinal cord in the fish. Is it of the 

 same dimensions throughout its length? Note the 

 numerous lateral branches. Are they single or in 

 pairs? These are distributed to the remaining parts 

 of the body. 



Examine the model of the human brain. Observing 

 the upper surface of the brain, note the two large con- 

 voluted (folded) hemispheres of the fore-brain, or 

 cerebrum. At the base of the cerebrum note the 

 smaller lobes of the cerebellum. How do the convolu- 

 tions on the cerebellum compare in size with those of 

 the cerebrum ? What is the color of each ? 



On the under surface of the brain, note again the 

 cerebral hemispheres and the cerebellum. How do 

 they compare in size? At the forward end of the 

 cerebrum note the two small white olfactory lobes. 

 Back of these note the two nerves which cross. These 

 are the optic nerv&s. The third portion of the brain 

 is the medulla oblongata. On the model it is the white 

 portion lying just beneath and in front of the cere- 

 bellum. Extending downward from the medulla is the 

 spinal cord which continues through the spinal column. 



Nerves are given off in pairs from the brain and 

 spwwl cord which continues through the spinal column. 



On the model of the longitudinal section of the brain, 

 locate the parts mentioned above. 



