CONTRIBUTIONS FROM THE ZOOLOGICAL LABORATORY OF THE 

 MUSEUM OF COMPARATIVE ZOOLOGY AT HARVARD COLLEGE. 

 E. L. MARK, DIRECTOR. — No. 147. 



THE COLOR CHANGES IN THE SKIN OF THE SO- 

 CALLED FLORIDA CHAMELEON, ANOLIS 

 CAROL1NENSIS Cuv. 



By Frank C. Carlton. 



Presented by E. L. Mark, October 14, 1903. Received September 30, 1903. 



Contents. 



PAGE 



I. Introduction 259 



II. The Histology of the Color Changes 260 



III. The Physiology of the Color Changes 264 



1. Introductory 264 



2. Brown Condition 265 



3. Green Condition 270 



4. Comparison witli other Lizards 272 



IV. Summary 274 



Bibliography 274 



Explanation of Plate 276 



I. Introduction. 



Although from the earliest times the color changes of the African 

 chameleon have attracted the attention of naturalists, a wholly satisfac- 

 tory explanation of these changes has not yet heen worked out. This is 

 probably due to the fact that the color changes in this lizard are very 

 likely the most complex of any in the reptiles, and that in consequence 

 their elucidation is proportionally more difficult. As Thilenius ('97) has 

 intimated, it would seem wisest to study first some of the simpler examples 

 of color change, and thereby obtain a clue to the explanation of those in 

 the more complex forms, like the chameleon, rather than to take up the 

 most complex first. In pursuance of this idea I have undertaken the 

 study of the color changes in the skin of the so-called Florida chameleon, 



