168 University of California Publications in Zoology. [Vol. 4 



The contrast between the stiffness and obstinacy of this large 

 old starfish, and the ready pliability and modifiability of the 

 smaller and yonnger ones was most noticeable throughout the 

 experiments. It is probably mainly to this that the lack of suc- 

 cess with H is due. 



The experiments described above establish clearly the ready 

 formation of temporary habits, and the slower formation of 

 habits lasting at least a week. While these experiments represent 

 a very large amount of tedious work, they are of course very 

 incomplete and represent only a preliminary, orienting study of 

 the matter of habit formation in the starfish. It would now be 

 possible with the methods and results thus far worked out as a 

 basis, to make a systematic study of the factors on which habit 

 formation depends; to develop, as it were, a system of educa- 

 tional methods for the starfish. By beginning with young speci- 

 mens, it is probable that striking results would be reached. Such 

 an investigation would require steady application to extremely 

 dull and tedious work, for a long period. 



Two or three special points may be spoken of briefly, rather 

 as general impressions from my experience, than as deductions 

 from precise and extensive data. 



The formation of the habit shows itself, as is clear from the 

 account given above, simply in a greater tendency to employ a 

 certain ray or a certain pair of rays in the reaction, not in tak- 

 ing on an absolutely fixed and invariable way of reacting. Con- 

 sideration of all the facts shows clearly why this should do so. 

 The direction of the righting impulse is determinable by many 

 factors, of which habit is but one. Often other factors work 

 against the habit factor. For example, the direction of the light 

 may tend to cause the animal to turn toward the right, the habit 

 toward the left. Sometimes one factor prevails, sometimes an- 

 other. The tendency given by the direction of the light rays 

 will sometimes be reinforced by the rays at the right being acci- 

 dentally the firet to come in contact with the bottom ; then these 

 two factors together are likely to overcome the tendency due to 

 the habit. When the many factors mentioned on pages 135 to 142 

 are taken into consideration, it is evident that we can not expect 

 a fixed and invariable habit to be formed, — certainly not without 



