COLORATION AND ITS INTERPRETATION 83 



Apparently no reptiles assume a special coloration in the 

 breeding-season comparable to the "nuptial plumage" of many 

 cock birds, or to the brilliant tints of the male crested newt at 

 the season in question. 



The fact that chamaeleons, which are for the most part uni- 

 formly coloured, have the power of changing the hue of their 

 skins according to the nature of their environment has long 

 been familiar, but it is less well-known that certain lizards are 

 endowed with the same faculty. The colour-change in chamae- 

 leons is due to the presence of pigment-bodies deep down in 

 the skin, which can be kept in that situation, or can be brought 

 near to the surface at the will of the reptile. When the pigment 

 is deep-seated, the skin appears dirty white or yellowish ; when, 

 on the other hand, it is allowed to come near the surface, the 

 colour becomes dark or even blackish ; while in the intermedi- 

 ate condition a greenish hue results from the diffusion of the 

 dark colour through the outer layers of the yellowish skin, and 

 by the iridescent character of certain elements in the latter. 



The colour of the common chamaeleon is practically inde- 

 scribable, so great and so frequent are its liabilities to change, 

 although there is great individual variation in regard to the 

 frequency, duration, and extent of the changes. The normal 

 coloration may be described as greyish green, with a number 

 of darker specks and two series of pale brown patches on the 

 sides of body, and a single patch near the ear. At night the 

 prevalent hue is creamy yellow, with irregular blotches of 

 yellow. Under the influence of excitement, as when in the act 

 of striking a fly, the normal diurnal tints are intensified, the 

 pale brown patches deepening to a full maroon, while the green 

 is dotted with spots of golden yellow. Passion seems to cause 

 these golden spots to turn blackish green. Very noteworthy, 

 as showing the economy with which natural phenomena are 

 conducted, is the fact that in many instances it is only the ex- 

 posed side of the body that turns green when the animal is 

 moving or sitting among foliage in daylight ; the concealed 

 side being yellowish white. Direct sunlight leads to a general 

 darkening of the colours ; and it is remarkable that in some in- 

 stances the normal green hue, with or without the dark blotches, 

 is retained during the night. 



As chamaeleons form a subordinal group (the Rhiptoglossa) 



