A CHAMELEON-LIKE CHANGE IN DIEMYCTYLUS. 1 



(PRELIMINARY REPORT.) 

 CHARLES G. ROGERS. 



In connection with some work done upon the heliotropic re- 

 sponse in the salamander Diemyctylus viridescens, it was noticed 

 that under certain conditions the animals changed color within a 

 few hours in a most remarkable manner. The following paper 

 is a report of the results obtained in a study of some of the con- 

 ditions affecting this color change. 



That light and heat are active stimuli in the case of many ani- 

 mals is a well-known fact. It has also been shown repeatedly 

 that not only do these stimuli affect the movements and orienta- 

 tion of the animals, but may, in some instances at least, bring 

 about changes of color as well. 



The literature upon this part of the subject is not extensive, so 

 it is impossible at present to formulate any general rule with 

 respect to which these changes may take place. It may be said, 

 however, that there is a remarkable uniformity in the results 

 obtained by different investigators. 



In attempting to explain the pigmentation of the salamander, 

 Salamandra maculata, Fischel 2 found that the temperature to 

 which the animals were subjected was an important factor. He 

 observed that the larvae of the salamander which developed in 

 warm water were of a lighter color than those which developed 

 in cold water. If dark-colored larvae were placed in warm water 

 they became lighter in color, the degree of the change varying 

 with the age of the larvae at the beginning of the experiment. The 

 newly-hatched larvae were found, also, to be much more suscep- 

 tible to the changes in temperature than the older larvae. As the 

 larvae became older the effects of the temperature to which they had 

 been subjected tended to become fixed. If light-colored larvae 

 were placed in colder water, the converse change was noticed, 



1 From the Zoological Laboratory of Syracuse University. 



2 Fischel, Arch.f. Mikr. Anat., XLVI., pp. 719-748. 



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