EXPERIMENTS ON MED US^E 



FIG. 7. 



LOCALISING REFLEX IN TIAROPSIS 

 INDICANS. 



" central nervous system " has only a conventional 

 significance. Romanes found that if we stimulate a 



o 



spot a (Fig. 7) on the concave side of the umbrella 

 of a Tiaropsis indicans with a needle, the manubrium 

 is brought to the 

 stimulated spot 

 (Fig. 7), as though 

 the animal wished 

 to remove the 

 stimulating object 

 (2). This move- 

 ment takes place 

 as follows: A 

 bending of the 

 manubrium as T 



If the point a on the margin is stimulated, the 



Well as Of the bell manubrium is brought to the stimulated spot, 



ensues in that mer- somewhat as a decapitated frog tries to wipe off 



. a drop of acetic acid with its foot. 



idian of the um- 

 brella which passes through the stimulated point a. 

 It seems as though all the muscle-fibres cooperated 

 in bringing the manubrium to the stimulated spot. 

 The central nervous system has nothing to do with 

 this reaction, for Romanes found that it continued 

 after excision of the whole margin with the nerve- 

 ring. On the other hand, if we make an incision 

 in the umbrella parallel to the margin and stimulate 

 a spot below the line of incision, movements of 

 the manubrium, although not pronounced ones, ap- 

 pear in the direction of the quadrant where the 

 stimulated spot is located, but an exact localisation 



