70- 

 from the faot that the stimulation o tha doreal 



myodermal sheath of the ray JLj; not an essential factor In the 

 reaction* 



If the righting reaction is simply a modification of ordin- 

 ary locomotion, it -would be expected first that contact stimulations 

 on the doraal myodarmal sheath of the ray do not play an essential 

 part in the ordinary locomotion and second, that, since the looomotor 

 impulse persists in a given direction for some length of time, the 

 righting reaction in the locomotor specimen shows a direction which 

 is very closely correlated with locomotion before and after righting. 

 Several laige active starfish were picked up when in rapid 

 locomotion and balanced inverted with the central part cf their disks 

 resting upon the bottom of a snail inverted beaker. Care was taken 

 in the manipulation to touch only trie disk and not to remove the 

 animals from the water or subject them to any other unnecessary stim- 

 ulation* In evary case two or more of the rays started to bend down 

 (dorsally) while the rays on the opposite side began to bend up* The 

 latter movements were more rapid than the former and the starfish coon 

 overbalanced and fell off the beaker* This was repeated so many tiates 

 that there is no doubt in my mind that the dorsoflexion and ventre- 

 flexion results of the operation of the "unified impulse" persisting / t 

 from the locomotion* That these movements are homologous with the 

 early righting movements (Jennings type 1) is indicated by the fact 

 that the rays which turn down turn also, usually, toward each other*# 



# This conclusion is rendered more probable by the fact that 

 some of the neurotomized starfish when coordinated in locomotion 

 would show righting movements if inverted quickly and gently* These 

 movements were similar in direction to those of the normal animal 

 but were complicated by the fact that sooner or later these animals 

 tended to take the "tulip form". (Romanes and wart 1881). In a 

 few cases they righted themselves quite promptly. 



