THE SKATE. 



71 



Fig. 22. — Raja nasuta. Dorsal view of the brain and anterior part 

 of the spinal cord, with the cerebral and anterior spinal nerves (half nat. 

 size). 



On the left side the 2nd, 5th, and 7th — loth cerebral nerves are 

 removed, and on the right side the 3rd, 4th, and 6th. The spinal 

 nerves are shown only on the left side : the distal end of the left 

 olfactory lobe is not shown. 



Central Nervous System, my, spinal cord : m.o, medulla 

 oblorigata : v. 4, fourth ventricle : c.r, corpora restiformia : cb, cere- 

 bellum : o.l, optic lobes: ih, thalamencephalon : ^. ,4, prosencephalon : 

 elf,- olfactory lobes. 



Nerves. /, olfactory : //, optic : ///, oculomotor : i.r, branch of 

 oculomotor to internal rectus : s.r, to superior rectus : it.r, to in- 

 ferior rectus: i.o, to inferior oblique: JV, patheticus : F", dorsal, 



