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bulletin: museum of comparative zoology. 



The results of the tests are shown in Table 5. In these tests the 

 three eyeless toads used for the experiments just described were again 

 employed. Each toad was given 64 trials, the total number of trials 

 for each region being therefore 192. A period of fifteen minutes was 



TABLE 5. 



The reactions of eyeless toads to local skin illumination by blue light. 



The numbers under + indicate total numbers of reactions toward the light; 

 under — , away from the light; under ± , without reference to the light (indifferent) ; 

 under 0, no reaction within fifteen minutes. 



again given each toad in which to react. It will be seen, by referring 

 to Table 5, that positive responses were obtained when each of the 

 three regions described was exposed to the light; but that the per- 

 centages of indifferent reactions, and of no reactions, were high, as 

 compared with the results obtained when only the skin was exposed. 

 This, of course, reduced considerably the percentage of positive 

 responses which, as the Table shows, was not much above fifty, the 

 percentage of negative responses being almost identical in the three 

 cases. There was no evidence to show that one region was more 

 sensitive to this form of stimulation than the others, which agrees 

 with the results obtained by Pearse (:10) for white light. Payne (:07) 

 has also obtained similar results on Amblyopsis. Parker (:05), 

 however, found the tail of Ammocoetes to be the most sensitive region 

 of the skin, and both Reese (:06) and Pearse (:10) found the same for 

 Cryptobranchus. Reese, however, also noted that the head of 

 Necturus was more sensitive than the tail, due probably to stimulation 

 received through the eyes. Pearse (:10) showed that, when the eyes 

 of Necturus were removed, the tail was the most sensitive region. 



The results of these experiments may now be briefly stated as fol- 

 lows : the reactions of eyeless toads were similar to those of hooded 



