ANATOMY AND SUBDIVISION OF NERVOUS SYSTEM 111 



their functions are probably intermediate between those of the 

 organs of touch in the skin and those of the internal ear, respond- 



Olfactory bulb 



Olfactory nerve 



(n.I) 

 Somatic area 



r. ophthal. superfic. V 

 r. ophthal. superfic. VTI 



n. terminalis 



r. ophthal. profundus V 



Optic nerve (n. II) 



r. mnxillaris V 

 r. mandib. V 



Supra-orbital trunk 



Infra-orbital trunk 

 Ganglion V 

 '. palatinus VII 

 -Gang. I'cnifiili VII 

 Gang, later. VII 

 r. prespirac. VII 



Spiracle 



r. hyomandib. VII 



n. IX 

 n. X 

 r. lateralis X 



r. branrhialis X 

 r. intestinalis X 



Fig. 43. Diagram of the brain and sensory nerves of the smooth dog- 

 fish, Mustelus canis, from above. Natural size. The Roman numerals 

 refer to the cranial nerves. The olfactory part of the brain is dotted, the 

 visual centers are shaded with oblique cross-hatching, theacoustico-lah-ral 

 centers with horizontal lines, the visceral sensory area with vertical lines, 

 and the general cutaneous area is left unshaded. On the right side the 

 lateral line nerves are drawn in black, the other nerves are unshaded. 



