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divides into several small branches wliicli radiate under tlie macula and 

 end in it. The tibres of this nerve are much smaller than those of the 

 eristic nerve and since they do not stain differentially they cannot be 

 traced as readily as those of the eristic nerve. The fibres seem to originate 

 in the ganglion some distance behind those of the preceding nerve, 

 y. A pair of olfactory (?) nerves. Each nerve passes from the side of the pedal 

 ganglion thru the lateral foramen of the skull with , and below , the optic 

 tract. It then passes thru the optic cup below and behind the optic 

 ganglion to the edge of the lateral process of the skull which it pierces 

 or passes over and ends in the columnar epithelium of the olfactory pit. 

 Within the brain the fibres can be followed from the point of their exit, 

 obliquely upward to a point near the pleural ganglion. 



B. Other nerves. 



4. A pair of nerves arises from the back end of the ganglion some distance 

 above the origin of the statocystic nerves , in fact , at the extreme upper 

 edge of the ganglion. Each nerve pierces the septum that separates the 

 pedal and visceral ganglia and passing over the outer surface of the latter 

 enters the cartilage. In the cartilage the nerve divides and , leaving the 

 skull , ends in the cephalic and nuchal retractors. 



5. Two nerves arise on each side from the same part of the ganglion and 

 are perhaps one with the preceding nerve. One of these passes thru the 

 lateral foramen of the skull and probably innervates the upper and poste- 

 rior muscles of the eye. The other passes upward thru a foramen to the 

 upper part of the cephalic retractor. 



6. A pair of small nerves arises from the pedal ganglion a short distance 

 in front of the last mentioned nerves and each nerve passes forward and 

 upward around the oesophagus and then outward to the ventro-anterior 

 muscles of the eye. 



7. A pair of siphonal nerves arises from the posterior part of the lower 

 surface of the ganglion and each nerve passes at once thru a foramen in 

 the pedal process to the siphon. AVhile in the foramen the nerve gives 

 off a branch which enters the optic capsule. 



8. Immediately in front of the siphonal nerves there arises a median nerve 

 which goes thru the pedal process and is distributed to the muscles of 

 the lower side of the head. 



9. A pail- of nerves arises from the sides of the front end of the ganglion. 

 Each nerve passes outward and forward above the pedal process and the 



