324 'Journal of Comparative Neurology and Psychology. 



source of the stimulus. The ability to locate the source of chem- 

 ical stimulation appears to be rather poorly developed. The chief 

 dependence seems to be upon touch stimulation for the accurate 

 localization of the food and the certainty of seizing. The great 

 part which touch plays in obtaining food is still more clearly 

 brought out in the following experiments with objects which, to the 

 human tongue at least, are practically tasteless. 



Dearborn speaks of the avidity with which one animal seized 

 a piece of sheet rubber cut to represent a leech, implying thereby 

 that it was deceived by the appearance of the object. I find that 

 almost all my animals will take a piece of rubber of whatever shape 

 or color as soon as it is touched to the antennae, chelae or mouth 

 parts, will press it to the mouth and chew at it for from thirty 

 seconds to five minutes, and will then cast it aside. A piece ot 

 cotton batting was rolled into a wad and tied to the end of a string. 

 This of course would not sink, but as soon as it was touched to an 

 antenna that extended up to the surface of the water the animal 

 reared on its telson, seized the wad, pressed it to its mouth, and 

 chew^ed at it for two minutes. Not all of the animals would react 

 to the cotton, but about half of them did, and some of those that 

 did not would not react to meat either at the time. A more con- 

 clusive experiment was one with a small white pebble washed per- 

 fectly clean and suspended by a clean white silk thread, so that 

 there might be no coloring matter to afford a chemical stimulus. 

 When this was lying on the bottom of the aquarium or hanging 

 quietly suspended in the water the animals paid no attention to it. 

 If it was moved about in the water the animals did not make for 

 it but rather moved away. When it was touched to the antennae 

 or mouth parts, however, it was seized in 60 per cent, of the cases, 

 pressed to the mouth, and chewed from one to eight minutes. 

 From this we conclude that the feeding reflex may be called forth 

 by a touch stimulus as well as by a chemical stimulus, and we are 

 strengthened in the conclusion that the animal depends largely 

 on touch stimuli for localizing and capturing food. Abbott's 

 statement that crayfish capture ethestomoids must be accepted on 

 the assumption that the animals are borne directly against the chelae 

 of the waiting crayfish and then snapped at and seized. 



(2) Reactions to Vegetables. Experiments were made with 

 bits of apple, potato, turnip, carrot and onion. As the reactions 

 to all of these were practically alike, a detailed account of the 



