COLOR CHANGES IN REPTILES 541 



quite regularly, as an afterthought, after some time in low temperature. 

 Among the forms she studied, the one which was most active in the 

 winter was Uta stansburiana stejnegeri; and this species took on its pale 

 phase at a temperature as low as 25 °C — a behavior comparable with that 

 of amphibians. 



Seven of the iguanids became pale in darkness and dark in the light 

 (at moderate temperatures) but five species showed no differences in 

 light and darkness, being obedient only to temperature. Two species of 

 Xantusid available to Miss Atsatt responded to both light and high tem- 

 perature with the dark, phase, and would not take on the pale phase con- 

 sistently in either low temperature or darkness. In the light of the noc- 

 turnality of Xantusid, we might cudgel our brains for an interpretation 

 of this pecuUarity — except for the fact that Miss Atsatt's one gekkonid 

 species, Coleonyx variegatus, is just as nocturnal, and yet becomes pale 

 in high temperature and in darkness, and darkens in low temperatures 

 and in illumination. 



An influence of hue upon the dermal responses of a lizard {Anolis 

 carolinensis) has been shown by the interesting preliminary experiments 

 of Wilson. This Tlorida chameleon' is the little chap sold at circuses, 

 with the disastrous advice to feed it on sugar-water. It is usually hawked 

 while tied to a board covered with green baize, and the pitchman is care- 

 ful to keep in the shade — else the animals cease to 'match' the board, and 

 turn brown. This is the whole gamut of the animal's changes — from green 

 to brown; but it does truly equal that of its African namesake. 



Wilson fitted green cellophane covers over the eyes of the lizards, and 

 covered some glass jars with similar material. He found that the green 

 phase was always produced by darkness, the brown phase by bright light. 

 Any brown individual, placed in a green jar, became green. Green cello- 

 phane over the eyes induced the green phase. If the eyes were blacked 

 out, either white or green light induced the brown phase. If one eye was 

 covered with green cellophane and the other with black, the green phase 

 was assumed as perfectly as if both eyes were acting. A few animals with 

 green hoods, and in a green jar, became intemiediate in phase (yellowish 

 brown) ; but Wilson noticed that they seemed sluggish and were blink- 

 ing their eyes — hence it was only natural that they should be intermedi- 

 ate between the expected green phase and the brown one which they 

 would assume upon closing the eyes for an even greater part of the time 

 with the body exposed to light. 



