CARLTON. COLOR CHANGES OF THE FLORIDA CHAMELEON. 261 



clearly marked scutes, in which all the layers of the skin are considera- 

 bly thickened, the small tracts between the scutes being the thinnest 

 portions of the skin. The pigment is restricted to the regions under the 

 scutes, and in this respect Anolis resembles more or less closely the 

 chameleon as described by Brlicke ('52) and Keller ('95). 



So far as the color changes in Anolis are concerned, the active opera- 

 tions seem to be limited to the pigment of the derma, for in the epidermis 

 I have sought in vain for any signs of alteration. In the following de- 

 scription I shall therefore confine my attention to the pigment-bearing 

 organs of the derma. 



Keller ('95, p. 141), in his account of the skin of the chameleon, has 

 described five kinds of pigment bodies differing from each other essen- 

 tially in the kinds of pigment that they contain. All the pigment bodies 

 in the skiu of Anolis are easily referred to two, or at most three, of these 

 five kinds. The conspicuous black bodies of Anolis (Fig. 1, mela'ph.), 

 well buried in the derma and sending branching processes outward 

 toward the epidermis, correspond to the melanophores described by Keller. 

 The material (Fig. 1, ocli'ph.) that fills in the spaces between the pro- 

 cesses of the melanophores is bluish-green by reflected light, and cor- 

 responds both in position and character to Keller's layers of ochrophores. 

 It is possible that occasionally a deeper reflecting layer of whitish mate- 

 rial corresponding to what Keller calls the leucophore layer may be present, 

 but this is certainly exceptional in Anolis, if in fact it occurs in this lizard 

 at all. The two remaining types of pigment bodies in the chameleon, 

 erythrophores and xanthophores, were not identified in Anolis. 



Since the skin of Anolis presents two extreme conditions, dark brown 

 and pea-green, and since the active changes by which these conditions 

 are produced are limited to the two sets of pigment bodies in the derma, 

 I shall restrict the remainder of my account of the skin to these bodies, 

 beginning with the ochrophores. 



The ochrophore layer (Fig. 1, ocJiph.) consists of pigment masses 

 arranged in several irregular rows parallel with the surface rather than 

 in columns perpendicular to it, as in the chameleon. 



The physical properties displayed by this pigment in its relation to 

 light are of interest. When a section of skin is viewed under the micro- 

 scope with transmitted light, this pigment appears yellowish with a 

 slight tinge of green ; in reflected light it has a bright greenish-blue 

 tint, suggestive of the color assumed by the animal at night. 



Since the ochrophore pigment is readily dissolved in mineral acids and 

 is doubly refractive, as may be demonstrated under the polarizing micro- 



