98 A. M. REESE. 



there was a decrease in temperature of 21. Neither did an 

 increase of 2 1 or more cause any reaction unless the higher 

 temperature reached 40 or more. It would seem, then, that 

 Cryptobranchus is not sensitive to considerable changes in tem- 

 perature, but is very seriously affected by a temperature only 

 slightly higher than that of the human blood. 



THERMIC REACTIONS OF NECTURUS. 



As might be expected, perhaps, from its having gills, Ncctnrus 

 proved to be more sensitive to temperature variations than was 

 Crytobrctnchus. 



When transferred from water at o C. to water at 18 three of 

 the five animals showed little or no reaction, but the other two 

 darted about the tank in a curious, spasmodic way quite different 

 from their usual motions. When transferred from water at 18 

 to water at 32, three of the animals again showed but little 

 activity, while the other two struggled quite violently. When 

 put into water at 42 from water at 32 or lower, all of the 

 animals struggled as violently as did Crytobranchits. 



When put into water at 4 from water at 32 two of the 

 animals again showed marked activity, while the other three 

 were scarcely affected. A very short stay in the warm water 

 was sufficient to completely exhaust all of the Nectitrus, so that 

 they turned belly side up, but when returned to water of moderate 

 temperature they soon recovered. 



Ncctnrns is apparently sensitive to considerable changes in 

 temperature, both rising and falling, as well as to the higher tem- 

 peratures to which Crytobranchus responded. 



Other and more accurate experiments along these lines sug- 

 gested themselves, but on account of the lack of the necessary 

 facilities they had to be postponed. 



BIBLIOGRAPHY. 

 Adams, G. P. 



'03 On the Negative and Positive Phototropism of the Earthworm, Allolobophora 

 fredita (Sav. ), as determined by Light of different Intensities. Amer. Jour. 

 Physiol., Vol. 9, No. I, pp. 26-34. 



Carpenter, Fred. C. 



'05 Reaction of the Pomace Fly (Drosophila ampelophila) to Light, Gravity, 

 and Mechanical Stimulation. Amer. Nat., Vol. 39, Mch., pp. 157-171. 



