306 A. A. SCHAEFFER. 



contact with the carbon. The ameba came into contact with 

 the carbon later but the direction of movement was not on that 

 account changed. Although the stimulus from the carbon grain 

 was localized yet the resulting change in behavior involved the 

 whole ameba, for it broke up into a number of pseudopods of 

 which those on the right side of the ameba had of course no 

 direct relation whatever with the carbon grain. The meaning 

 of these pseudopods on the right is obscure, though pseudopods 

 are frequently formed in this way under such conditions as 

 surrounded this experiment. Orderly movement in clavate form 

 was disturbed by the sensing of the carbon grain, but after the 

 carbon grain was left behind, orderly movement was again 

 resumed. It should be noted especially that a pseudopod was 

 formed on the right side directly opposite the carbon. This 

 phenomenon is frequently observed in ameban behavior. A 

 number of cases are described in a previous paper (Schaeffer, 

 '16). See also Fig. 224 in this paper. Throughout the whole 

 experiment the general direction of motion was not changed, but 

 it could not be predicted from Fig. 259 in what direction the 

 ameba was then going to move. This experiment is a very 

 good example of the phenomenon of functional inertia (Schaeffer, 

 '12, '14) the tendency in an ameba to continue moving in the 

 direction in which it started to move about which I shall have 

 more to say later. 



A grain of carbon was placed in the path of a raptorial (see 

 footnote, p. 305) ameba 216. The ameba moved into contact 

 with the carbon, then forked and moved on through the right 

 prong. The carbon grain was then shifted so that it lay to the 

 right of the ameba's path 220. The ameba moved forward, 

 turning away from the carbon at first, but later a side pseudopod 

 was sent out directly toward it. When the ameba was about 

 forty microns from the carbon another pseudopod, further an- 

 terior, was also sent out toward the carbon. The posterior 

 pseudopod was the first one to come into contact with the carbon, 

 and as it continued moving forward, it pushed the carbon grain 

 along. The anterior pseudopod moved into contact with the 

 carbon. A pseudopod directly opposite the anterior one enlarged 

 and carried the ameba away. Both pseudopods extended toward 



