•320 Gil man A. Drew 



ting the cerebro-pedal connectives, stimulation of the ganglia 

 causes vigorous contractions of the w^iole foot, including the ante- 

 rior and posterior foot muscles. It was not determined w^hether 

 the foot muscles w^ere affected throughout or only in part. They 

 become so intimately connected with the general musculature of 

 the foot that a complete contraction of the foot would necessarily 

 involve them. 



The above experiments show the organs that are supplied with 

 motor nerves from each pair of gangha, but they do not indicate 

 whether the contraction was in each case caused by stimulating 

 cells in the gangha themselves or by stimulating fibers that might 

 be passing through them from other gangha. 



By isolating the different gangha and stimulating sensory areas 

 connected with them, motor cells can be proved to be present in 

 the cerebral and visceral gangha. Stimulating the sensory surfaces 

 was generally accomphshed by stroking with the point of a seeker 

 or pencil. If muscular organs connected with the ganglia con- 

 tracted upon such stimulation, motor cells must be present in the 

 ganglia. 



After cutting the cerebro-visceral and cerebro-pedal connectives 

 and the circum-palhal nerves (the latter near the siphons), strok- 

 ing the tentacles around the ventral mantle opening caused con- 

 traction of the anterior adductor muscle, and both sides of the 

 collar. After separating the visceral ganglia from the others by 

 cutting the cerebro-visceral connectives and the circum-palhal 

 nerves (the latter near the cerebral ganglia), stroking the siphons 

 apparently caused shght contractions of the posterior adductor 

 muscle and strong contractions of both sides of the posterior mar- 

 gins of the mantle. Stimulation of one of the pallial nerves elec- 

 trically, caused the siphons, posterior adductor and both of the 

 posterior mantle margins to contract. These experiments indicate 

 that sensory cells end in both the cerebral and the visceral ganglia 

 and that stimulating these fibers causes disturbances in the motor 

 cells in the same ganglia that cause the contractions mentioned. 



With the pedal gangha results are not so easily obtained. When 

 these gangha are separated from the others by cutting the cerebro- 

 pedal connectives, the foot immediately loses its rigidity, and any 



