SECTION OF NAKED-EYED MEDUS.E. 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 someiuhere ; for every 

 time any portion of tissue below the cut a 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 anothei-, 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 c, 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 



