EXPERIMENTS ON ARTHROPODS 121 



and forward the pieces of meat that are thus offered 

 them by the legs. 



As regards the further isolation of the ganglia that 

 are located posterior to the subcesophageal ganglion, 

 the facts which have been described in Limulus are 

 in general true. As long as the ganglion of a seg- 

 ment remains connected with the segmental organs, 

 the functions of that segment remain unimpaired. 

 Bethe has found single exceptions to this rule, but it 

 is conceivable that these exceptions are shock-effects 

 resulting from the operation. 



We will now report more briefly concerning Bethe's 

 experiments on some other Arthropods. 



5. Sqtiilla no longer swims spontaneously after the 

 supracesophageal ganglion has been isolated (that is, 

 after division of the commissure between the suprace- 

 sophageal ganglion and the mouth-ganglion). The 

 spontaneous progressive movements usually seem to 

 be destroyed. When stimulated, however, the ani- 

 mal moves normally. The nervous mechanism for 

 the locomotor reflexes is localised in the three ganglia 

 of the locomotor appendages, that is, these append- 

 ages still move normally, even though the connection 

 with the ganglia lying in front has been interrupted. 



In grasshoppers {Pachytylus cinerascens} isolation 

 of the supracesophageal ganglion causes the spontan- 

 eous progressive movements to cease. These animals, 

 after the operation, clean their antennae with their 

 fore-legs like a normal animal. According to Bethe 

 these localised reflexes of the legs are produced by 



