THE BEHAVOIR OF PROTOZOA 69 



object as if drawn by surface tenison; a small pseudopod is 

 put out on either side of the food; these processes extend 

 and curve around it until they meet, and then the object 

 is drawn into the endoplasm. In Amoeba proteus and limax 

 "there is no adherence between the protoplasm and the 

 food body," although there is adherence in Amoeba verrucosa 

 whose ectoplasm seems to be more adhesive to all kinds of 

 objects. 



Amoeba like higher animals may follow its food. Jennings 

 describes an Amoeba attempting to engulf a spherical cyst of 

 Euglena. As the Amoeba came in contact with it the cyst 

 rolled away; the Amoeba followed; the cyst continued to 

 be pushed ahead now one way and now another and the 

 Amoeba changed its course accordingly. After the cyst had 



Fia. 7. Reaction of Amoeba to a strong mechanical stimulus. The 

 arrows indicate the direction of the currents. 



been rolled against an obstacle and the Amoeba was about 

 to succeed in capturing it, a large infusorian appeared on the 

 scene and swept it away. 



The reactions of Amoeba to stimuli may be either positive 

 or negative. To a strong mechanical stimulus such as con- 

 tact with the point of a needle Amoeba reacts by crawling 

 away. Should the stimulus be applied at the anterior end 

 the stimulated part stops, there is a local contraction of the 

 ectoplasm and the granules begin to stream away from the 

 point of contact. This stream meets the stream proceeding 

 in the general direction of locomotion and the two combine 



