Fig. 46. Brain and spinal cord of frog x about 2. 

 Cerebral hemisphere. b. Olfactory lobe. c. Eye. d. Thala- 

 mencephalon. e. Optic lobes. f. Cerebellum. g. Medulla 

 oblongata. h. Fourth ventricle. i. Spinal cord. I. Olfactory 

 nerves. II. Optic nerve. III. Oculomotor nerve. IV. Pa- 

 theticus. V. Fifth nerve. VII. Facial nerve. VIII. Auditory 

 nerve. IX. Glossopharyngeal nerve. X. Vagus nerve. 1 10. 

 First to tenth spinal nerves. 2 and 3 unite to form the brachial, 

 and 7, 8, and 9, to form the sciatic plexus. [The sixth cranial nerve 

 is very small and is not shown.] 



