SECTION OF NAKED-EYED MEDUSZ. 113 
manubrium is no longer able to localize the seat of 
stimulation in the bell, it nevertheless continues 
able to perceive, so to speak, that stimulation is 
being applied in the bell somewhere; for every 
time any portion of tissue below the cut @ is 
irritated, the manubrium actively dodges about 
from one part of the bell to another, applying its 
extremity now to this place and now to that one, 
as if seeking in vain for the offending body. If the 
stimulation is persistent, the manubrium will every 
now and then pause for a few seconds, as if trying 
to decide from which direction the stimulation is 
proceeding, and will then suddenly move over and 
apply its extremity, perhaps to the point that is 
opposite to the one which it is endeavouring to find. 
It will then suddenly leave this point and try an- 
other, and then another, and another, and so on, as 
long as the stimulation is continued. Moreover, it 
is important to observe that there are gradations 
between the ability of the manubrium to localize 
correctly and its inability to localize at all, these 
gradations being determined by the circum- 
ferential distance from the end of the cut and 
the point of stimulation. For instance, in Fig. 22, 
suppose a cut A B, quarter of an inch long, to be 
made pretty close to the margin and concentric 
with it, then a stimulus applied at the point ¢, just 
below the middle point of A B, would have the effect 
of making the manubrium move about to various 
parts of the bell, without being able in the least 
degree to localize the seat of irritation. But if 
the stimulus be applied at d, the manubrium will 
