410 WM. A. KEPNER AND W. CARL WHITLOCK 
This current gains in velocity as it approaches the gullet; its 
velocity is greatly checked at the gullet, and by the time that 
it has passed the width of the body beyond the dorsal side of 
the Chilomonas, it has become quiet. The apparently quiet 
Chilomonas in this condition, therefore, disturbs the water within 
a very restricted area. The great majority of quiet Chilomonases 
are anchored by both flagella. These display a vibratory move- 
ment of short amplitude. But even in these cases we find the 
water is not remotely disturbed by the vibrations of the anchored 
Chilomonas. Not even the smallest suspended particles in the 
water were disturbed if they lay a body's length away from the 
vibrating animal. There is no other variation in the manner in 
which these animals disturb the surrounding water. The effect 
of Chilomonas upon the surrounding water seems, therefore, to 
be rather restricted (at no time passing beyond a body's length 
from the margin of the animal) and constant. 
The great variabihty of the reactions of ameba to the stimuh 
arising from this rather restricted and constant disturbance of 
the water stands in sharp contrast to the constancy of the source 
of its stimulation. Kepner and Taliaferro ('13) showed that 
the reactions of Ameba proteus toward Chilomonas are quah- 
tative ones. Our own observations on ameba feeding upon Chilo- 
monas indicate that these reactions are qualitative. For exam- 
ple, in figure 5 w^e have represented a situation in which the 
ameba's pseudopods are traveling about the Chilomonas on all 
sides at a distance of about the length of the latter's body. It 
would appear, therefore, that in this case the ameba is following 
the limits of the waves that radiate from the vibrating animal- 
cule. Many other examples might be given of amebas' making 
a much wider embrace of the Chilomonas, but there are some 
observations to be made that are more conspicuous in their 
contrast to the reaction recorded in figure 5. In the reaction 
shown in figure 21 there is no relation between the extent of the 
water's di^urbance by the Chilomonas and the ameba's mode of 
capturing its prey. For here the regions of the ameba's body 
that reacted by sending out secondary pseudopods lay down 
beneath the tip of the broad parent pseudopod, so that these 
