CONTRIBUTIONS FROM THE ZOOLOGICAL LABORATORY OF THE 

 MUSEUM OF COMPARATIVE ZOOLOGY AT HARVARD COLLEGE. 

 E. L. MARK, DIRECTOR. — No. 127. 



STUDIES ON THE REACTIONS OF LIMAX 

 MAXIMUS TO DIRECTIVE STIMULI. 



By Peter Frandsen. 



Presented by E. L. Mark. Received September 3, 1901. 



II. 



Introduction .... 

 Tliigmotaxis .... 

 Material and Methods 



Results 



Geotaxis 



Methods ... 

 Operations and Results 



CONTENTS. 



Page 

 185 

 187 

 187 

 188 

 190 

 190 

 191 



Summary of Part II . 



III. Pliototaxis 



Methods 



Operations and Results 

 Summary of Part III 

 Bibliography . . . 



Page 

 205 

 206 

 208 

 209 

 225 

 22G 



Introduction. 



The following studies were made at Harvard University during the 

 fall and winter of 1898-99. The problem was proposed by Dr. C. B. 

 Davenport and the investigation carried on under his immediate direc- 

 tion. I wish here to acknowledge my indebtedness to his many sugges- 

 tions and helpful criticisms throughout the year. In connection with the 

 preparation of the manuscript for publication, I am under obligation to 

 Dr. E. L. Mark for many kindnesses. 



The behavior of any organism toward artificial stimulation is prob- 

 ably always largely dependent on its normal environmental condi- 

 tions. The long action of those conditions, assisted, perhaps, by the 

 animal's own efforts, conscious or unconscious, to adapt itself to them, 

 finally results in certain habits and instincts. The process of adaptation 

 being extremely slow, organisms are strongly averse to great or sudden 

 changes in their environment and incapable of adjusting themselves to 

 them. As a rule, then, we should expect animals to seek those condi- 

 tions of light, heat, moisture, and other physical and chemical influences 

 which are most in accordance with those to which they are normally 

 subjected. 



