126 



W. J. CROZIER. 



conspicuous, so that a fairly definite region could be distinguished 

 as an " anterior " in creeping. From the typical records sub- 

 mitted, it appears that as a rule either the longest ray, or a long 

 ray near a madrepore, is the " directive " ray. 



As to the relative importance of ray-length and position of 

 madrepore, it seems clear that, atlhough no absolute rule can be 



2.8 



20V 



cms. 



IY 



FIG. 5. Figs. 4 and 5 show typical instances of the " physiological anterior " 

 in Coscinasterias (see Table V) ; i, ii, . . ., numbers assigned to rays ; lengths 

 of rays in cms.; madrepores, black; predominant directions of locomotion 

 under non-directive stimulation shown by arrows. 



