FOOD-REACTIONS OF AMEBA PROTEUS 405 
13). At 10:15 A.M. the Paramecium was fmi-her constricted and 
the ameba quiet (fig. 14). At 10:25 a.m. the cytoplasmic isth- 
mus of the Paramecium's body was stretched and the ameba dis- 
played a httle movement along pseudopod c and threw out pseu- 
dopods a and h about the projecting portion of the Paramecium, 
the ciha of which were quite active (fig. 15). Pseudopods a and 
h were soon withdrawn. At 10:35 a.m. the constricting and 
stretching of the isthmus of cytoplasm were increased and the 
isthmus was flexed (fig. 16). By 10:43 a.m. the flexing of the 
enclosed cytoplasm had become very conspicuous (fig. 17). Two 
minutes later a pseudopod, d, was sent out along one side of the 
projecting lobe of the Paramecium's body, the cilia of which were 
yet quite active. This secondary pseudopod was at once with- 
drawn, while the Paramecium was further stretched and bent. 
At this phase of the reaction a Cyclidium darted into the field 
and lay near the free end of a large 'anterior' pseudopod. The 
ameba reacted to this animal at once by sending out pseudopods 
e and / and capturing the smaller ciliate (fig. 18). The Para- 
mecium was now released by the ameba as it ingested the Cy- 
clidium. The constricted, elongated portion of the mutilated 
Paramecium shortened greatly and the large ciliate swam off 
under its 'own steam,' having a contour about like the outhne 
given in figure 19. No trace of cilia could be seen on the part 
of the Paramecium's body that had been ingested by the ameba. 
An ameba may ingest food at different parts of its body syn- 
chronously. We have observed one ingesting five Chilomonases 
at one time and at five different regions of its body. Moreover, 
the two types of food reactions may be carried on simultaneously. 
On January 28, 1919, while an ameba was ingesting a quiet fila- 
ment of Oscillatoria, a Chilomonas came to lie beneath the fila- 
ment at a position indicated in figure 20. The Chilomonas was 
lying beneath the plane in which the filament of Oscillatoria lay. 
The ameba advanced about the plant until pseudopod h was 
formed. This pseudopod then sent out an encircling wall of 
cytoplasm about the Chilomonas and then overarched it with 
an ectoplasmic film. The space within which the Chilomonas 
was thus taken was next divided into a larger and a smaller 
