MAR 12 1903 



MOVEMENTS, ETC, OF FRESH-WATER PLANARIANS. 509 



The Movements and Reactions of Freshwater 

 Planarians: a Study in Animal Behaviour.^ 



By 



Rayinoiid Pearl, Ph.D. 



(Instructor in Zoology in tlie University of Michigan, Ann Arbor, 

 Michigan, U.S.A.) 



Contents. 



A. Intkoduction . 



B. IResume of Literature . 



I. Morpliological and Systematic 

 II. Piiy si logical 

 c. Material 



D. Habits and Natural History 



I. Occurrence and Distribution 

 II. Activities 



a. Sensitivity 



h. Secretion of Mucus 



c. Periods of Activity and Rest 



(1. Formation of Collections . 



e. Movement on Surface Pilni 



III. Food 



IV. Defecation 



V. Summary of Factors in Behaviour 



E. Normal Motor Activities 



I. Locomotor Movements 

 a. Gliding 



1. Rate of Gliding Movement 



2. Direction . 



PAGE. 

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 ol5 

 548 



' Contributions from the Zoological Lal)oratory, University of Michisan, 

 Ann Arbor, Michigan, No. 58. 



VOL. 46, PART 4. NEW SERIES. L L 



