102 ^ PHYSIOLOGY FOR THE LABORATORY. 



c. The motor oculi, or motor nerves of the eye, arise from 

 the inner surfaces of the crura cerebri in front of the 

 pons Varolii. 



d. The pathetic! curve around the front edge of the 

 pons ; they originate a little posterior to the corpora 

 quadrigemina. 



e. The trigeminals are large and conspicuous and arise 

 from the sides of the pons. 



f. The abducens arise just posterior to the pons. 



g. The facial nerves are seen at the lower edge of the 

 pons, nearly in a line with the fifth pair. 



h. The auditory nerves are just outside the seventh pair, 

 and cling to the lateral surface of the medulla. The 

 glosso-pharyngeal, the pneumogastric, the spinal accessory, and 

 the hypoglossal, each arises by several roots which form a 

 line on the lateral part of the medulla. Consult a draw- 

 ing of the human brain. 



i. Add the nerves to your ventral view of the brain. 



D. The Interior of the Brain. 

 I. A LONGITUDINAL SECTION. 



Make a median longitudinal section of the entire brain, 

 taking great care that it is exactly in the median line. 



Identify : 



a. All the parts that you have seen on the dorsal and 

 ventral surfaces. 



b. The gray matter constitutes the outer layer, or cortex. 

 Is it composed of cells or fibres ? How is it arranged with 

 reference to the fissures ? How thick is it ? 



