n] HABITS OF CONVOLUTA 71 



the attitude of attention which it takes up during 

 the " up " period we do not know. Nor may we say 

 Avith confidence that the explanation of the periodic 

 rhythm which we have offered is complete or final. 

 The subject deserves more detailed study than it has 

 yet received, both for its own sake and for the light 

 which it may throw on the origin of habit and, it 

 may be, also, of instinct, 



