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 Ameba proteus and limax 
“there is no adherence between the protoplasm and the 
food body,” although there is adherence in Ameba verrucosa 
whose ectoplasm seems to be more adhesive to all kinds of 
objects. 
Ameeba like higher animals may follow itsfood. Jennings 
describes an Amceba attempting to engulf a spherical cyst of 
Euglena. As the Amceba came in contact with it the cyst 
rolled away; the Amceba followed; the cyst continued to 
be pushed ahead now one way and now another and the 
Ameeba changed its course accordingly. After the cyst had 
a b 
Fic. 7:—Reaction of Amceba to a strong mechanical stimulus. The 
arrows indicate the direction of the currents. 
been rolled against an obstacle and the Amceba was about 
to succeed in capturing it, a large infusorian appeared on the 
scene and swept it away. 
The reactions of Amceba to stimuli may be either positive 
or negative. To a strong mechanical stimulus such as con- 
tact with the point of a needle Ameeba 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 
