FIG. 27. The nervous system of the edible frog (Rana esculenta), from the 

 ventral surface. From Ecker. 



F., facial nerve ; G., ganglion of pneumogastric nerve ; He., cerebral hemisphere ; Lc., optic 

 tract ; Lop, optic lobe ; M., boundary between medulla oblongata and spinal cord ; M. i-io, the 

 spinal nerves ; MS., connection between fourth spinal nerve and sympathetic chain; N., nasal sac ; 

 Ni., sciatic nerve ; No., crural nerve ; o., eyeball ; S., trunk of sympathetic ; S. i-io, the sym- 

 pathetic ganglia ; Sp., continuation of sympathetic into head. 



I., olfactory nerve ; II., optic nerve ; III., motor oculi ; IV., fourth nerve ; V., trigeminal and 

 facial nerves ; Va., ophthalmic branch of trigeminal ; Vc., maxillary branch of trigeminal ; Vd., 



ramus anterior of glossopharyngeal ; Xz., ramns posterior of glossopharyngeal ; X. 3-4, branches 

 of pneumogastric. 



