92 WILLIAM A. KEPNER AND ARNOLD RICH 



3. Finally, we have in our third experiment a case in which 

 a posterior part of the body was amputated so as to leave at 

 least two-thirds of the proboscis projecting free (fig. 4, A, B, 

 C). Here the possibility of mechanical injury of the con- 

 trolling portion of the central nervous system during the opera- 

 tion is much less, and yet the proboscis immediately became ac- 

 tive and turned anteriorily in an effort to ingest part of the 

 body to which it was attached. The proboscis in this specimen 

 soon underwent autoamputation. 



This last is a strikingly exceptional case and is the only example 

 in which we have it suggested that thigmotactic stimuli, inde- 

 pendent of nervous control, are factors in the inhibitory control 



Fig. 5 B, anterior and posterior extremities removed. On attempting to 

 open sheath with needle points, proboscis underwent autoamputation. 



of the proboscis. Even here there may have resulted an injury 

 of the ganglia or nerves of the proboscis, so that the breakdown 

 of the inhibition was due to nervous injury and not to thigmo- 

 tactic disturbances. We have, therefore, no clear case that shows 

 that thigmotactic disturbances will alone excite the proboscis 

 into abnormal activity. 



Our experiments, however, indicate that the central nervous 

 system acts as an inhibitor to the proboscis. Not all of the 

 central nervous system seems to be directly concerned with this 

 inhibitory control. 



1. The dorsal ganglia of a specimen were amputated (fig. 6, 

 A), and no marked disturbance of the proboscis followed. Ten 

 minutes later a second cut was made midway between the base 



