3 66 



MANUAL OF ELEMENTARY ZOOLOGY 



The cranial nerves resemble in number and general 



distribution those of the frog, but the presence 



r " eB ' of the gills and other differences in the arrange- 



Fig. 



-The brain of Ihe dogfish, seen from above. 



cb., Cerebellum; <rr., cerebrum; ///..>., medulla oblongata; <>//./., olfactory lobe 

 olf.o.i oifactory organ ; op,, ophthalmic branches o( Fifth and seventh nerves 

 fip.L, optic lobes ; p,st., pineal stalk ; r./\, restiform body ; sp.c, spinal cord 

 s/>./i., spinal nerve ; ///-(/., thalamencephalon ; ^ 4, third and fourth ventricles 

 //.-)'., VI1.-X., cranial nerves. 



