IIG JELLY-FISH, STAR-FISTI, AND SEA-URCHINS. 



end of the section (the section being of the form 

 represented by A B in the figure). These relations, 

 as we have seen, are the more favourable to correct 

 localization : (a) the greater the radial distance be- 

 tween the point of stimulation and the end of the 

 section ; and (6) the less the circumferential distance 

 between the point of the stimulation and the radius 

 let fall from the end of the section. But we have 

 seen that the limits as regards severity of section 

 within which these gradations of localizing ability 

 occur, are exceedingly restricted — a cut of only a 

 few millims. in length, even though situated at the 

 greatest radial distance possible, being sufficient to 

 destroy all localizing power of the manubrium as 

 regards the middle point of the corresponding arc 

 of the margin, and a stimulus applied only a 

 few millims. from the attached end of a severed 

 marginal strip entirely failing to cause localizing 

 action of the manubrium. Lastly, we have seen 

 that even after all localizing action of the manu- 

 brium has been completely destroyed by section of 

 the kinds described, this organ nevertheless con- 

 tinues actively, though inefiectually, to search for 

 the seat of irritation. 



The last-mentioned fact shows that after excita- 

 tional continuity of a higher order has been 

 destroyed, excitational continuity of a lower order 

 nevertheless persists ; or, to state the case in 

 other words, the fact in question shows that after 

 severance of the almost exclusively radial connec- 

 tions between the bell and the manubrium, by 

 which the perfect or unimpaired localizing function 



