322 'Journal of Comparative Neurology and Psychology. 



receptive of chemical stimuli. This in'dicates that there are 

 chemical receptive organs on all parts of the body. Whether 

 these organs are more numerous on the anterior appendages 

 or not, more decided and definite reactions are obtained from 

 the stimulation of these members. All the observations are in 

 agreement with Bethe's statement that the mouth parts are more 

 sensitive than the antennules. Indeed both the chelae and the 

 first and second chelipedes respond more readily to chemical stim- 

 ulation than the antennules. The accuracy of localization of a 

 chemical stimulus on various parts of the body is considerable, as 

 is evidenced in the experiments with acids and salt, where not only 

 the member but even the very spot stimulated was frequently 

 rubbed. Characteristic reactions were dropping the antennules 

 and wiping them with the maxillipedes, quickly orienting the 

 mouth to a meat juice stimulus, grasping with the chelae and cheli- 

 pedes and bringing them to the mouth as though holding food, 

 bowing up on the telson w^hen the ventral surface of the abdomen 

 was stimulated and pantomimic passing of food to the mouth 

 in the case of meat juice or digging at the pleopods with the 

 chelipedes in the case of acids and salt, and vigorous retraction 

 and rubbing of the eyes from salt and acids. 



8. Feeding. — More important in the ordinary life of the organ- 

 ism than mere reactions to chemicals is the question to what extent 

 and in what manner does the animal's reception of chemical stim- 

 uli assist it in obtaining food .^ In other words, how quickly and 

 accurately does the animal orient itself to a chemical stimulus 

 whose source is some distance away .? What part does the chemi- 

 cal sense and what part do sight and touch play in procuring food .^ 



(i) Reactions to Meat. In the air no reactions whatever were 

 obtained to meat. The animal paid no attention to a bit of meat 

 swung near it, and when the piece was touched to the antenna 

 or antennule the onlv movement was one of avoidance. If held 

 between the forceps of the chela the meat would sometimes be 

 grasped but more often the chela would be withdrawn. When 

 grasped the bit of meat was carried to the mouth in one case only 

 and then soon discarded. This is what was to be expected, as the 

 animal probably never eats anything in the air. 



When first brought into the laboratory the animals will not eat 

 anything even in water. It usually requires some two or three 

 weeks for them to become sufficiently accustomed to their environ- 



