PARKER AND STARRATT. — COLOR IN ANOLIS CAROLINENSIS. 463 



room that throughout the winter retained a rather high uniform tem- 

 perature (18° to 20°), whereas ours were begun in one whose temperature 

 was subject to much variation. 



Before turning to a general discussion of our results comment should 

 be made on the bearing of these conclusions on certain conditions ob- 

 served in Anolis under natural surroundings. Judging from their 

 reactions to light as recorded by Carlton (:03), we should expect these 

 animals in their native haunts to be brown in the daytime and green at 

 night. "VVe have never had the opportunity of studying Anolis in the 

 field, but through the kindness of Dr. Caswell Grave we have been 

 informed that in the neighborhood of Beaufort, N. C, on a hot, sunny 

 day about as many green animals may be taken in bright sunshine as 

 brown ones. This is in all probability a mixed reaction, in that some of 

 the animals are more sensitive to light than to heat and hence turn 

 brown in bright sunlight, and others are more sensitive to heat than to 

 light and hence turn green under like conditions. 



IV. Discussion of Results. 



The brown state in Anolis, which corresponds to the dark gray or 

 black state of many fishes, amphibians, and other reptiles, is dependent 

 upon the accumulation of pigment in the fine peripheral branches of the 

 melanophore cells of the derma. The green state, on the other hand, 

 is possible only after this pigment has withdrawn into the body of the 

 melanophore cell. We may therefore conclude that a low temperature, 

 such as 10°, induces a migration of the pigment toward the periphery 

 and a high one (40° or 45°) a migration toward the centre. 



Thus far very few records of the migration of the pigment of chromat- 

 ophores in relation to temperature have been published, but such as have 

 appeared support the conclusions just stated, and suggest for them a 

 much broader application. Thus it seems clear that in the African 

 chameleon the melanophores draw in their pigment and the skin becomes 

 light when the animal is subjected to heat, for Briicke, though he 

 ('51, p. 804) declared that dark heat rays had no effect in changing the 

 color of the skin, stated ('52, p. 26) that when the animal was put in 

 an atmosphere that warmed its skin to 30° it became lighter colored. 

 Moreover this observation was confirmed by Keller ('95, p. 129), who 

 observed that when a chameleon was subjected to heat at 30° to 38° it 

 took on a lighter tint than usual and retained this even untler strong 

 illumination, where it would be expected to become dark. 



