No. 474] 



RE AC 



'LARIA 



403 



mer bends toward the point of stininlation and ii few or all of tlie 

 distal tentacles wave about for a short tinu'. It' in this process 

 they touch some object, they then close up around the mouth. 

 When the stimulation is very strong, the manubrium shortens and 

 both sets of tentacles close up around it. 



The hydranths will submit to considerable mechanical stimu- 

 lation without reaction. For example, a stream of water forced 

 from a pipette upon an exj)auded individual will cause no move- 

 ment unless the current is rather strong. 



If a proxiuud tentacle is pulled vigorously, the manubrium will 

 turn so that the mouth is brought toward the stimulated point and 

 the distal tentacles will open out. However, as each set of ten- 

 tacles may be made to react independently ami witlioin apparent 

 influence on the other set, it seems probalilc that in ilii- case the 

 manubrium is strained and thus stimulated directly. 



The reactions described above are d()ul)tless helpful to the animal 

 in securing food, though they are not i)erfectly adajned to this pur- 

 pose. They are not very accurately adjusted to the gathering of 

 food, for the proximal tentacles will always move toward the mouth 

 even when the point of stinuilation is on the outer face, in wliich 

 case they move directly away from what may l)e food. 



When a proximal tentacle is touche.l with a piece of meat at any 

 point, it bends toward the mouth. The meat, if it is on the inner 

 face of the tentacle, is pressed against the mouth for a time and 

 then the tentacle slowly returns to its former place. All the {)roxi- 

 mal tentacles often close up in the presence of meat, but those in 

 contact with it react first and remain closed after the others have 

 opened out, which they usually do quickly. If meat is placed very 

 gently on the proximal tentacles, no reaction takes place and it falls 

 off or remains re-ting upon them. Sometimes when meat is placed 

 upon them, the bending reaction takes place, but this is so feeble 

 that the meat does not move far enough to reach the distal tentacles 

 and in such cases there is no movement of the manubrium or distal 

 tentacles. When meat comes in contact with tho distal tentacles, 



