XII 



CHANGES OF COLOUR 



571 



striated iridescent cells of the Malpighian layer. Those parts into 

 which the chromatophores do not send pigment appear as yellow 

 spots. The chromatophores are to a great extent under control 

 of the will of the Chameleon, 

 but external stimuli, as heat and 

 cold and other reflex actions, 

 also play a great part in their 

 movements. 



For further information on 

 this subject see Briicke, 1 P. Bert, 2 

 Pouchet, 3 Thilenius, 4 and lastly 

 Keller, 5 who has written a very 

 long but rather confused account. 



The process of moulting is FIG. 150. Diagrammatic section through 



the skin of a Chameleon. Highly 

 magnified. C, deeper portion of the 

 cutis ; Ch, three chromatophores, in 

 various stages of contraction, filled 

 with black, brown, or reddish pig- 

 ment ; , epidermis ; IT, white layer 

 of granules ; Y, yellow layer of cells. 



curious. When the Chameleon 

 is in good health the whole 

 process is accomplished within a 

 few hours. The skin to be cast 

 off becomes loose and assumes a 

 blistered appearance. Sometimes the creature looks as if it were 

 wrapped up in white, semi-transparent tissue paper. By rubbing 

 against stones, or between the twigs of trees, the skin conies off 

 in large flakes, first on the lips, then on the contorted body, and 

 last on the under surface of the hands and feet. During a rapid 

 and successful moult the changes of colour go on as usual in the 

 new skin. Sometimes large flakes of the old skin remain 

 adherent for days, especially on the top of" the head. The 

 moulting takes place several times in one year. One of my 

 Ch. vulgaris moulted in January and September, and then not 

 until June of the next following year. A Ch. pumilus moulted 

 in the months of May, October, and March. 



When they know themselves to be discovered, Chameleons 

 make themselves as thin as possible by compressing the body or 

 rather the belly. This is done by means of the peculiarly 

 elongated abdominal ribs described above. The whole body is 

 then put into such a position that, by presenting only its 

 narrow edge to the enemy, it has become as little visible as 



1 Denk. Ak. Wien. iv. 1852. 2 C. R. Ass. Franc. Ixxx. 1876, No. 21. 



3 J. de I'anat. physiol. viii. 1872, p. 401. 



4 Morphol. Arbeit, vii. 1897, p. 515. 5 Arch. Physiol. Ixi. 1895, p. 123. 



