TKOPIC AND SHOCK EEACTIONS IN PEKICH^TA 

 AND LUMBKICUS. 



E. H. HARPER. 



From the Zoological Laboratory of Northwestern University. 



With Two Figures. 

 CONTENTS. 



PAGE 



lutroductiou 569 



Movements of Pericliaeta 569 



Methods of Stimulation 572 



Chemical Stimulation of the Anterior End 572 



Negative reaction types 573 



Relation to the musculature ' 575 



Frequency of the reaction types under different degrees of stimulation 576 



Variability of the types 576 



The tropic tendency in the different reaction types 578 



The two-phased character of the reaction types 580 



"Unterschiedsempfindlich" responses 580 



Reactions to Light 581 



Note on Experiments with Electrical Stimulation 584 



Conclusions 584 



Summary 585 



Literature List 587 



Intkoduction. 



Perichseta bermudensis (Beddard) is an exotic earthworm of 

 active habits found in greenhouses. Members of this genus are 

 frequently known as eel-worms. Its movements are more complex 

 than those of our common species. A description of some of the 

 movements will be given preliminary to a consideration of its reac- 

 tions. 



Movements of Perichwta. — 1. Locomotion of the usual type. 



2. Polling with the middle of the body in advance. In this 

 maneuver the middle region extends causing a stretching of the 

 The Journal of Comparative Neurology and Pstcholoqt. — Vol. XIX, No. 5. 



