258 



PRACTICAL ZOOLOGY 



on 



fv 



hn 



sv 



FIG. 147. Nervous system and sense organs in the head of the frog. 



1, cerebrum; 2, mid-brain; 3, optic lobes; 4, cerebellum; 5, medulla. 



e, eye ; fv, first vertebra ; gpn, glosso-pharyngeal nerve ; hn, first spinal 

 nerve ; ie, internal ear ; no, nasal opening ; on, olfactory nerve ; os, olfactory 

 sacs; p, pneumogastric nerve ; sc, spinal cord ; sv, second vertebra; ^tympa- 

 num; tn, trigeminal nerve. (After Jammes.) 



