MOVEMENT AND PROBLEM SOLVING IN OPHIURA 



BREVISPINA^ 



BY 



O. C. GLASER 



With Five Figures 

 INTRODUCTION 



The observations and experiments which I shall describe and 

 discuss in the following pages were made in the Marine Biological 

 Laboratory at Wood's Hole, for the purpose of testing Preyer's 

 conclusion that ophiurans are intelligent animals. In spite of 

 the fact that there is still much difference of opinion as to what we 

 mean by intelligence, all will agree, I think, that it involves at 

 least the ability to learn and to modify behavior in accordance 

 with experience. Jennings ('06, p. 291) has formulated in the law 

 of the resolution of physiological states, the way in which behavior 

 is modified in experience: "The resolution of one physiological 

 state into another becomes easier and more rapid after it has 

 taken place a number of times." I have attacked the problem of 

 intelligence in Ophiura brevispina from the point of view afforded 

 by this law of resolution. 



PROGRESSION 



Progression in ophiurans has been described by a number of 

 observers, including Romanes ('85),Preyer ('86),von Uexkiill ('05) 

 and Grave ('00) . These writers agree as regards the general method 

 of locomotion in ophiurans, but they have not described all of the 

 movements which these animals >perform. All of these authors 

 have noticed two types of progression, the first of which may be 

 visualized by the aid of Fig. i, in which the arms are numbered, 

 and so distinguished by heaviness of line, that the most active is the 

 widest, the least active the narrowest. 



* Contributions from the Zoological Laboratory, University of Michigan, No. 107. 

 The Jourxal of Experimental Zoology, vol. iv. no. 2. 



