236 Journal of Comparative Neurology. 



It is not a forced movement as Fauvre and Steiner sup- 

 pose ; does not depend upon a center of direction (Fauvre) sit- 

 uated in the brain ; nor is it a general center of motion (Stein- 

 er), since after removal of the inhibition of the uninjured side 

 through applied stimuli forward motion and even cii'ciis motion 

 to the injured side may be called forth in any of the animals 

 experimented upon except the Brachyura (Carcinus), in which 

 here the circus motion to the right or left (toward the uninjured 

 side) is a forced one. This rests on the fact that upon the 

 operated side the lateral motion becomes impossible, and for- 

 ward motion appears in its stead, while the legs of the unin- 

 jured side continue to go sidewards. 



3. In the case of animals with negative phototropism it 

 was established that this property is lost after longitudinal split- 

 ting of the brain (Carcinus, Astacus, Hydrophilus). As for 

 Carcinus the same effect could be produced by removal of the 

 globuli. 



4. The mouth ganglia ( suboesophageal ganglion ) are 

 in no arthropods (that I have investigated) the seat of all co- 

 ordination of motion. In the case of Astacus and Carcinus 

 they play the greatest role ; here progressive motion, the possi- 

 bility of holding the body on its legs, or of turning over when 

 placed on its back are all lost. Paralysis, however, is not 

 caused in a single segment of the posterior animal, and other 

 complicated reflex actions as the motions of eating, of cleaning 

 body and legs, etc., are still retained (Astacus, Carcinus). The 

 effect of the removal of the mouth ganglia is not so marked in 

 Squilla, Pachytylus, Apis and Hydrophilus. Progressive mo- 

 tion is still possible for Squilla, and in addition that of turning 

 from the dorsal to the ventral position for the other three ; the 

 wing movements for flying in the case of the grasshopper and 

 the bee ; the reflex actions of swimming in the case of Hy- 

 drophilus, and of jumping in the case of Pachytylus ; that is to 

 say, all that the posterior animal is able to do is retained, — 

 only there is in general a certain awkwardness and feebleness in 

 the mentioned activities. 



5. The degree of independence of the individual thor 



