114 JELLY-FISH, STAR-FISH, AND SEA-URCHINS. 
probably be so far able to localize the seat of irrita- 
tion as to confine its movements, in its search for the 
offending body, to perhaps the quadrant of the bell 
in which the stimulation is bemg applied. If the 
stimulation be now supplied at e, the localization 
on the part of the manubrium will be still more 
accurate ; and if applied at f (that is, almost beneath 
one end of the cut A B), the manubrium may suc- 
eeed in localizing quite correctly. 
These facts may also be well brought out by 
another mode of section, viz. by cutting round a 
greater or less extent of the marginal tissue, leaving 
one end of the resulting slip free, and the other end 
attached in situ. If this form of section be 
practised on Tiaropsis indicans, as represented at 
g & in the figure, it may also be observed that 
irritation of a distant poimt in the marginal strip, 
such as g or h, causes the manubrium to move in 
various directions, without any special reference to 
that part of the bell which the irritated point of 
the marginal strip would occupy if im situ. But if 
the stimulation be applied only one or two millims. 
from the point of attachment of the marginal strip, 
as at 7, the manubrium will confine its localizing 
motions to perhaps the proper quadrant of the bell; 
and if the stimulus be applied still nearer to the 
attachment of the severed strip, as at 7, the localizing 
motions of the manubrium may become quite 
accurate. 
Again, with regard to radial distance, if the cut 
A B in the figure were situated higher up in the 
bell, as at A’ B’, and the are, ¢, d,e, f, of the 
