PRACTICAL ZOOLOGY 



fv 



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 ; t, tympa- 

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



