64 CHARLES W. HAIIGITT 



temperature had fallen to 15 C. and both had grown almost 

 white in color. Here we have one of the many examples of 

 color change which negatives Parker's rules. The light through- 

 out had been practically the same; hence the reaction must 

 have been quite apart from any influence from that source. 



Experiment. A jar containing three specimens was used, and 

 the room temperature was found to be 21 C. At this the color 

 of two was a grey over back, with distinct green on sides; that 

 of the third distinctly darker and without trace of green. The 

 jar was next placed on outer window shelf where the temper- 

 ature was 4 C. One of the greenish specimens continued abso- 

 lutely unchanged ; a second became distinctly lighter and the 

 green disappeared ; the third remained in same position and 

 color just as at beginning of experiment. After about an hour 

 specimen No. 1 had become distinctly lighter, much like 2. 



This experiment was repeated on a subsequent day. At 

 the first, one specimen was very bright diffuse green, the other 

 two were very dark colored. Room temperature about 21 C. 

 The jar was placed on outer shelf where temperature was again 

 4 C. They remained here for more than half an hour and with 

 only this color change, viz., the green specimen had become 

 greener, the color having extended to the legs and become more 

 intense. The color of the others had remained as at the be- 

 ginning. 



These experiments were variously repeated on these speci- 

 mens, but in the same general manner, and with results so 

 similar as to call for no special account. The following ob- 

 servations may be noted. On one day in early morning the 

 temperature of the room had fallen quite lower than usual, viz., 

 12 C. Two frogs were found crouched under the moss and both 

 very light, whitish grey; a third was crouched on top of the 

 moss and very uniformly dark over body and legs. In the 

 afternoon they were again observed, the temperature having 

 become about normal, 20 degrees, and while all had continued 

 in same positions, the two under the moss had become quite 

 darkly colored, the other remaining as before. 



Other temperature experiments will be described in con- 

 nection with the account of H. arbor ea, and any special remarks 

 and discussion may be deferred to a later time. Enough has 

 been submitted, however, to confirm the suggestion made in 



