3IO A. A. SCHAEFFER. 



out and later forked and flowed on under the glass fragment. 

 The same piece of glass was again laid before the ameba, but 

 the behavior does not show definitely that the glass was sensed 

 at a distance. The same piece of glass was then shifted and 

 again laid to the left of the ameba's path 160. The ameba 

 moved forward a short distance, then sent out a pseudopod on 

 the left directly toward the glass 162. The pseudopod was 

 called forth doubtless by the agitation of the needle in placing 

 the glass in position, for hungry raptorial amebas are readily 

 thus stimulated. But the glass was actually sensed in Figs. 

 163 and 164, for the pseudopod directed slightly to the right of 

 the glass turned so as to go directly toward the glass. After 

 coming into contact with the glass a pseudopod was formed on 

 the convex side of the main pseudopod, a region especially favor- 

 able to the formation of new pseudopods, through which the 

 ameba moved away. A new piece of glass was then laid before 

 the ameba 168. A pseudopod was thrown out on the right 

 through which the ameba moved on 169-171. This pseudopod 

 turned strongly to the left toward the glass. When about eighty 

 microns from the glass 172 a pair of opposite pseudopods 

 were formed near the tip of the main pseudopod. The left 

 member of this pair of pseudopods moved directly toward the 

 glass. When almost in contact with the glass this pseudopod 

 \vas retracted 173. The ameba moved away through the main 

 pseudopod. The same piece of glass was again laid before the 

 ameba 175. The ameba moved toward it a short distance, 

 when a pair of opposite pseudopods were formed near the tip 

 of the main pseudopod 177, 178. As the ameba moved past 

 the glass, another pair of opposite pseudopods were formed 

 near the tip of the main pseudopod 178. Neither of these 

 pseudopods moved far before they were retracted 179, 180. 

 Before the ameba moved out of sensing distance of the glass, it 

 turned strongly to the left and encircled the glass through 180 

 at a distance of about sixty microns. Two pseudopods, soon 

 to be retracted, were formed on the convex side of the ameba 

 during the latter stage of the encircling reaction 181, 182. 



A small fragment of glass was laid in the path of a granular 

 ameba 194. The ameba broke up into several pseudopods, of 



