VERTBBRATA. 87 



2. Observe also a vein (renal portal) connected with 



the outer border of each kidney. 



3. Draw the kidneys with their veins. 



li. The Spinal Nerves. 



The spinal nerves lie in pairs against the dorsal 

 body wall. 



1. Identify ten pairs of spinal nerves. 



2. Where do they originate and what is their relation 



to the backbone ? 



3. Trace each pair to find out what part of the body it 



supplies. 



4. Which are the largest nerves? Why? 



5. Which run together or unite to form a sort of 



network (plexus)? 



6. Draw. 



M. The Brain and Spinal Cord. 



The brain and '"spinal cord form a large, white, soft 

 tube seen when the backbone and the skull are 

 laid open. The anterior lobed portion is the 

 brain. 



1. Why are the brain and cord so carefully protected? 



2. The Brain. 



a. Identify, beginning at the anterior end, — 



(1) the olfactory lobes, two small lobes from each 



of which a nerve (olfactory) passes to the 

 nostrils ; 



(2) the cerebral lobes, two large, elongated lobes; 



(3) the optic lobes, two rounded lobes ; 



(4) the cerebellum, a single, very small, median 



lobe ; 



