AMEBOID MOVEMENT 115 



apparent connection between longer waves and darkness has not 

 yet been investigated. 



Figure 36 shows the path of an Amoeba proteus under con- 

 trolled light conditions as above described, but instead of moving 

 over a polished plate glass surface as in the previous experiments, 

 the ameba in this experiment moved over a fine ground-glass 



"11:45 



Figure 36. Showing how smooth waves in the path of an Amoeba pro- 

 teus in clavate shape become disturbed by the projection of prominent 

 pseudopods. Although there was considerable disturbance due to the 

 formation of pseudopods at 11:53 the conformation of the wave was 

 not changed until the stage preceding the one at 12:07, when the forma- 

 tion of numerous pseudopods resulted in an irregular path. Length of the 

 ameba, about 600 microns. 



surface. It will be observed that for the first twenty minutes 

 the path shows smooth waves, although at 1 1 153 and 1 1 155 there 

 was a slight disturbance which was associated with the formation 

 of numerous pseudopods. From 12:07 on > however, the path 

 becomes irregular, the wave-like character being almost obliter- 

 ated. Associated with this irregularity is the presence of numer- 

 ous pseudopods. This is a sample of a number of records which 

 indicates that in proteus and discoides the presence of numerous 

 pseudopods in some way prevents the ameba from moving in a 

 path marked by smooth and conspicuous waves. 



\\hen a wave in the path for some reason becomes unusually 

 long, there is likely to be a very abrupt and decided change in 

 the direction of movement, which is away from the convex side 

 of the wave. Figure 37 is inserted here to illustrate this point. 

 The ameba should have turned to the left at 3:43 to keep the 

 waves of typical size, and at 3 45 a pseudopod was extended 

 in this direction a short distance, but again the curve toward the 

 right persisted. But at 3 :48^2 the ameba broke up into several 

 pseudopods at right angles with the main axis, and through one 



