256 OILMAN A. DREW. 



PLATE XXII. 



Fig. 9. Cerebral and pedal ganglia with their nervous connections, as seen 

 from the antero-ventral position. These ganglia and the otocysts lie in a mass of 

 connective tissue and may be dissected out and mounted for study without injury 

 Magnified about fifteen diameters. 



Fig. 10. Visceral ganglia seen from the ventral side. These may easily be ex- 

 posed for study by stripping the thin muscular covering from their ventral surfaces. 

 They are hard to separate from the adductor muscle but they may be mounted with a 

 thin piece of the muscle and studied in position. Magnified about fifteen diameters. 



apn, anterior pallial nerve; bn, branchial nerve; cc, cerebral commissure; eg, 

 cerebral ganglion ; cpc, cerebro-pedal connective ; cvc, cerebro-visceral connective ; 

 fn, foot nerve; of, otocyst ; otc, otocystic canal; otn, otocystic nerve ; pg, pedal 

 ganglion ; /, palp nerve; ppn, posterior pallial nerves; x, swelling on the visceral 

 ganglion from which the anterior root of the branchial nerve originates ; y, swelling 

 on the visceral ganglion from which the posterior pallial nerves originate. 



