Vol. X] VON GELDERN—SKIN OF ANOLIS CAROLINENSIS 81 



II Mid-dorsal stripe: 



a. Pink with irregular brownish border. 



b. Brick-red with irregular brownish border. 



c. White or cream color with irregular brownish border, 



d. Black with fairly regular border. 



e. Brown or green matching surrounding skin. 



III Post-orbital patch: 



a. Black. 



b. Various shades matching the rest of the body. 



IV Ventral surface of the body : 



a. White. 



b. White with scattered black spots. 



c. Dirty brown or gray. 



On comparing this table with that of Briicke for Chamceleon vul- 

 garis, one notices certain differences. For instance, pale flesh 

 colors, lilac gray, steel blue and purple are not present in Anolis, 

 but the greater simplicity which Carlton would attribute to the 

 latter is questionable. Undoubtedly differences exist but the 

 changes must be just as complicated in one as in the other. 



Causes of Color Changes 



The most evident general factors influencing the color states 

 are light, absence of light, temperature, and various external 

 stimuli. 



Carlton found that with few exceptions the brown state was 

 brought about from the green state in four minutes by exposure to 

 sunlight. Absence of light changed the brown to green in twenty- 

 five minutes. With specially constructed containers, he found 

 that, with few exceptions, if part of the body of a green lizard, 

 either head or body, be exposed to direct sunlight, while the rest 

 remained in the dark, the entire body became brown. 



Carlton concludes that there are nerve terminals in the skin 

 which are directly sensitive to light and which, when stimulated 

 in one area, send impulses which reach the efferent nerve endings 

 of the skin over the entire body. Spinal cord section in no way 

 changed the results, indicating that the action is either wholly 

 reflex in character, or that spinal nerves do not necessarily influence 

 the changes. Carlton was able to induce the green state by in- 

 jections of .001% nicotin solution in small quantities and this 

 change from brown to green was brought about in one minute. 

 This suggested to him that this change is under the control of the 

 S3anpathetic nerves. 



