18 LEON J. COLE 



39). On the other hand, specimen No. 6 has a broad 'path/ 

 indicating that although the impulse was directed toward the 

 same general region it vacillated considerably from side to side. 

 It was noted that specimens Nos. 4 and 5 were I'elatively stiff 

 or rigid and comparatively inactive, while No. 6 was flexible 

 and moved at a good rate throughout the fifty trials. This 

 fact may or may not be of significance. 



The slant of the 'path' is similarly a measure of the 'rotation' 

 of the impulse as a whole. This was not correlated in any defi- 

 nite way with the condition of the starfish, so far as could be 

 observed, but during the course of the experiments the impres- 

 sion was gained that an individual was often comparatively 

 inactive during the first few trials — that it had to be put over 

 the course a few times before it became 'waked up to the work,' 

 so to speak — and in a number of cases at least it slowed down 

 toward the end of the experiments as if becoming fatigued* (for 

 example, see No. 5, which refused to crawl after the forty-fourth 

 trial). In this connection it may be pointed out that a consider- 

 able number of the cases (Nos. 2, 5, 6, 7, 8, 9 and 10) seem to 

 show a tendency to start at the sides of the diagrams (in the 

 regions or arms b and c), to cross the space diagonally, and to 

 end again at the opposite side below. If the impression stated 

 above is true, then this means that in general when the experi- 

 ments were started with the various specimens they were com- 

 paratively inactive and tended to crawl 'backward' (if we admit 

 that a physiological 'anterior' has been established), i.e., with 

 the general region be in advance; gradually the impulse swings 

 around until they are crawling 'foi-ward;' and finally as they 

 become fatigued, it moves on around to the original position. 

 This matter should have been tested by continuing the trials 

 much further, but it was not realized at the time, and there 

 appeared no obvious reason why fifty trials with each individual 

 were not sufficient. 



Whether or not the above relations prove to be general, never- 

 theless the records do seem to establish beyond a doubt the 



^ Glaser ('07, p. 206) mentions changes from active to sluggish behavior and 

 the reverse, in Ophiura, for which there was no obvious explanation. 



