PLATE XII. 



c. g. 

 c. c. 



ps. g. 

 ps. c. 



p- g- 



pe. c. 



The nerves dissected from 



Cerebral ganglia. 



Commissural cord connect- 

 ing cerebral ganglia. 



Posterior ganglia. 



Commissural cord connect- 

 ing the cerebral and pos- 

 terior ganglia. 



Pedal ganglion. 



Commissural cord connect- 

 ing the pedal and cerebral 

 ganglia. 



the animal and enlarged. 



g. n. The nerve whose branches 



supply the gills, 

 b. n. The nerves of that part of 

 the mantle constituting 

 the inhalent and exhalent 

 siphons. 

 . m. n. Anterior mantle nerve. 

 p. m. n. Posterior mantle nerve, 

 au. s. Auditory sac. 

 a. a. n. Anterior adductor nerve, 

 p. h. n. Peripheral nerve. 



