Mr Edwards 07i Change of Colour in the Chameleon. 317 



lighter shade. Finally, on the inner surface of the skin, this 

 deep hue appeared still more intense. 



In those parts of the skin which did not exhibit this purple 

 colour, there was only to be seen, on the external surface, a yel- 

 lowish-grey tint, more decided over the cutaneous tubercles, 

 than in the intervals by which they were separated ; and in some 

 patches along the sides, and on the under part of the body, it 

 was whiter than elsewhere ; whilst on the upper parts of the 

 back it inclined more to pure yellow. When the skin was ex- 

 tended so as to stretch the tubercles with which it is studded, 

 no apparent change was produced on the colour ; but, on ex- 

 amining its inner surface, there was universally found the same 

 violet-red colour, approaching to black, which, in certain places, 

 was seen from without as well as from within. 



It appears then evident, that there exists throughout, in the 

 integuments of this animal, two pigments which are quite dis- 

 tinct, viz. one of a grey colour, more or less yellowish or white, 

 according to the parts on which it is observed, and another of 

 a violet or blackish red ; and that the differences of colour which 

 I have noticed were owing to this circumstance — that sometimes 

 the latter membranous pigment was seen at the surface through 

 the scarfskin, more or less intermingled with the former, whilst, 

 again, at other times, it was hid under the greyish membrane. 



This fact being established, it became probable that the for- 

 mation of the purple spots of varying hues which were ob- 

 served in a transient way during the life of the animal, and af- 

 terwards vanished altogether, depended on certain alterations in 

 the position of the lower membrane. The mixture of its tint 

 with the hue of the more superficial layer, can in truth easily 

 explain all the phenomena which are observed during life. And 

 I was only confirmed in this opinion by the change which 

 was exhibited a little while after death. As we liave pre- 

 viously noticed, the dark red hue extended itself nearly over the 

 whole surface of the body ; but on placing the animal upon 

 a marble slab which was somewhat cold, I observed that the 

 spots became paler, and in certain places vanished altogether. 

 In those points where the colour had undergone this change, 

 the darker pigment was no longer visible under the scarf-skin, 



VOL. XVII. NO. XXXIV. — OCTOBEU 1834. Y 



